Sweet Onion Confit

Caramelized onion jam is a truly remarkable savory homemade preserve, offering a burst of sweet and tangy flavor that elevates ordinary dishes into culinary delights. It’s perfectly suited to enhance a gourmet sandwich, a juicy burger, or an elegant charcuterie plate. When prepared correctly, this versatile jam can be safely processed for long-term storage using a water bath canner, allowing you to enjoy its exquisite taste year-round. Alternatively, for those seeking a quicker option, it can be made in a smaller batch as a simple refrigerator preserve, ready to be savored within a few weeks.

Unlocking Flavor: The Magic of Caramelized Onion Jam

Caramelized onions are culinary superstars, renowned for their ability to infuse almost any savory dish with incredible depth and sweetness. Imagine capturing all that rich, complex flavor in a jar, ready to be enjoyed anytime, right from your pantry shelf. That’s precisely what you achieve with homemade caramelized onion jam. This exceptional recipe not only offers the convenience of a quick refrigerator preserve but also provides detailed instructions for water bath canning, ensuring a stable, delicious addition to your kitchen arsenal for months to come.

While most people are intimately familiar with the vibrant sweetness of fruit jams, such as classic strawberry jam or old-fashioned grape jam, savory jams have, regrettably, often been overlooked. This oversight is a true culinary shame! Historically, these savory preserves were cherished for their ability to introduce exciting new dimensions and layers of flavor to everyday meals, transforming a mundane plate into something truly special with a rich, flavorful dollop.

This exquisite onion jam is more than just a condiment; it’s a gourmet enhancer. It beautifully elevates a sophisticated charcuterie board, adding a touch of rustic elegance. But its utility extends far beyond just appetizers.

You can effortlessly spread this homemade savory onion jam on various sandwiches, transforming a simple grilled cheese from ordinary to extraordinary. Its deep, umami-rich notes complement creamy cheeses and crusty bread perfectly.

I am particularly enthusiastic about using caramelized onion jam on homemade burgers. It takes an otherwise standard family meal and elevates it to the level of a gourmet brew pub offering. The sweet, tangy, and savory notes cut through the richness of the meat, creating a harmonious flavor profile that will impress everyone at the table.

Some might refer to this delightful creation as an onion relish or an onion preserve, and honestly, the name doesn’t diminish its deliciousness. In my culinary lexicon, it’s undeniably a savory jam, and its incredible flavor transcends any linguistic classification.

Essential Ingredients for Crafting Your Caramelized Onion Jam

This meticulously tested recipe for caramelized onion jam is a thoughtful adaptation from Naturally Sweet Food in Jars by Marisa McClellan. Her entire book is a treasure trove of innovative approaches to home canning without relying on refined cane sugar, exploring creative alternatives like fruit juices and natural sweeteners such as honey.

In this particular recipe, maple sugar plays an absolutely pivotal role. It is not merely a substitute for granulated sugar; it is an integral component that defines the unique character and exceptional flavor of this jam. Without it, the jam would simply not achieve the same depth and richness. However, if maple sugar is genuinely unavailable, light brown sugar can be used as a last resort, though the flavor profile will differ slightly.

For those who have maple syrup on hand, creating your own maple sugar is a straightforward and rewarding process. You can follow instructions on how to make maple sugar, which essentially involves cooking maple syrup until it crystallizes. This crystallization step is crucial for this recipe, as it removes excess water from the syrup before it’s incorporated into the jam, preventing a watery or “soupy” consistency. Alternatively, you can conveniently buy maple sugar online if you prefer.

Choosing the Right Onions for Flavor Perfection

The original recipe suggests red onions, and they certainly yield a beautiful, vibrant jam. However, I’ve personally achieved outstanding results with various onion types. In fact, I often find that the most intensely flavored yellow onions—the kind that make your eyes water profusely during chopping—produce the best jam. The higher concentration of sulfur compounds in these pungent onions directly translates to a more profound and complex flavor in your finished preserve. Red onions and sweet onions will also work wonderfully, though the resulting jam might be a tad milder in flavor.

To prepare approximately 4 half-pint jars of this exquisite caramelized red onion jam, you will need the following high-quality ingredients:

• 1 Tbsp neutral cooking oil, such as sunflower, grapeseed, or even a good quality olive oil for a subtle fruity note.
• 3 pounds of fresh onions, finely sliced. (This typically equates to 6-8 medium onions, or about 10 cups once halved and sliced.)
• 1 cup maple sugar (essential for its unique flavor and consistency; see notes above for alternatives).
• 2 Tbsp bottled lemon juice (crucial for canning safety and balance of flavor).
• 1½ cups quality cider vinegar (contributes tang and acts as a preservative).
• 2 teaspoons kosher salt (enhances flavor and aids preservation).

Slicing 3 pounds of onions can be quite a task, and those powerful fumes can be challenging. A clever trick to save your eyes from tears is to wet your hands and arms before you begin chopping. Onion fumes are attracted to water, so providing an alternative target on your skin can significantly reduce eye irritation, allowing for a tear-free slicing experience.

After all that slicing, you’ll inevitably have a generous amount of onion peels. Don’t discard them! I always save onion peels to make flavorful homemade broth and stock. They are packed with vitamins and contribute a wonderful depth of flavor and beautiful golden color to homemade vegetable stock or rich chicken broth or stock.

Should you not have kosher salt on hand, feel free to substitute with coarse sea salt or pickling salt. These options provide similar salinity and purity suitable for canning.

The unique and versatile flavor profile of caramelized onion jam is so captivating that you’ll likely find yourself wanting to prepare multiple batches. This jam masterfully achieves the distinct, robust flavor of onion without any harsh spiciness, balanced perfectly with a delicate touch of sweetness. Unlike traditional fruit jams, this onion jam recipe relies on the acidity of vinegar and lemon juice for safe preservation, completely bypassing the need for pectin.

As mentioned, maple sugar is an ingredient not commonly found in many canning recipes, but it’s a star here. While you can certainly purchase maple sugar, making your own from maple syrup is surprisingly simple and often much more economical than buying it pre-made.

Step-by-Step Guide: How to Make Caramelized Onion Jam

If you’re new to the world of hot water bath canning or simply need a refresher, I highly recommend consulting my comprehensive Beginner’s Guide to Water Bath Canning before you start. This will ensure you understand all the safety protocols and proper techniques. For those who prefer immediate gratification, you can absolutely skip the canning process and enjoy this as a refrigerator or freezer preserve; it will still be incredibly delicious!

1. Prepare Your Canning Setup (if canning): Before you begin cooking, ensure your water bath canner is filled with enough water to cover your jars by 1-2 inches. Start heating it to a simmer. Have your clean jars, two-part canning lids (bands and flats), and other essential tools like a jar lifter, canning funnel, and headspace tool ready.
2. Initiate Caramelization: Measure the cooking oil into a large, heavy-bottomed pan or Dutch oven. Heat the oil over medium-high heat until it appears thinner and shimmers slightly. Add the thinly sliced onions to the hot oil and stir thoroughly to ensure all the onions are well coated.
3. Slow Cook for Sweetness: Immediately reduce the heat to very low. This step is critical. Cook the onions for a patient 45 to 50 minutes, stirring frequently to prevent sticking. Resist the urge to rush this process by increasing the heat, as your goal is to gently reduce and soften the onions, allowing their natural sugars to develop and caramelize slowly, without browning or charring.
4. Onion Reduction Check: After cooking, the onions should have significantly reduced in volume, typically to about half of their original amount, becoming translucent and deeply fragrant.
5. Introduce Maple Sugar: Add the maple sugar to the pot with the caramelized onions. Stir vigorously until the maple sugar is completely dissolved into the onion mixture.
6. Intensify Flavors: Increase the heat to medium-high and continue to cook the onion and sugar mixture for 3 to 4 minutes, stirring constantly. You’ll notice the distinct aroma of the hot, sweet sugar as it melds with the onions.
7. Add Acids: Carefully pour in the cider vinegar and bottled lemon juice to the onion/sugar mixture. Be prepared for it to “spit” and bubble vigorously at first due to the temperature difference. It’s crucial to avoid leaning directly over the pot to prevent inhaling the strong vinegar vapors. Stir well to fully incorporate the liquids.
8. Season and Simmer: Reduce the heat back to medium, then add the kosher salt. Allow the onion mixture to simmer gently for another 10 to 12 minutes. During this time, the vinegar will reduce and thicken, transforming into a luscious, sticky syrup, and the onions will become perfectly soft and tender within the liquid. The final consistency should be a thick, glossy onion syrup.
9. Jarring the Jam: Remove the pot from the stove. Working swiftly while the jam is hot, use a canning funnel to ladle or pour the caramelized onion jam into your hot, sterilized jars. Leave a precise ½-inch headspace from the rim of the jar.
10. Prepare for Sealing: Using a clean, damp cloth, carefully wipe the rims of each jar to ensure they are free from any food residue, which is essential for a proper seal. Apply the two-part canning lids, tightening the rings only to “finger-tight” (just snug enough, no overtightening).
11. Cool or Can: If you are making a refrigerator preserve, simply let the jars cool completely on your counter before transferring them to the refrigerator. If you are canning for shelf stability, proceed to the canning instructions below.

Mastering Water Bath Canning for Caramelized Onion Jam

For long-term, shelf-stable storage of your homemade caramelized onion jam, water bath canning is the ideal method. This process ensures food safety by creating a vacuum seal that prevents spoilage.

1. Prepare Jars: After cooking the jam, ladle or pour the hot onion jam into your prepared hot jars using a canning funnel, ensuring a consistent ½-inch headspace from the top of each jar.
2. Clean Rims and Seal: Thoroughly wipe the rims of the jars with a clean, damp cloth to remove any food particles. This step is crucial for achieving a secure seal. Attach the two-part canning lids (flats and bands), tightening the bands only to “finger-tight.”
3. Process in Canner: Carefully place the filled jars into your already simmering or boiling water bath canner, using a jar lifter. Ensure that the jars are completely submerged under at least 1-2 inches of water. Bring the water back to a full rolling boil, then begin your processing time. Process the jars for 10 minutes, making sure to adjust this time based on your altitude (see detailed altitude adjustments below). Maintain a consistent boil throughout the entire processing period.
4. Cool Down: Once the processing time is complete, turn off the heat source under the canner. Remove the canner cover and let the jars remain in the hot water for an additional 5 minutes. This allows the internal temperature of the jars to equalize, reducing the risk of “siphoning” (liquid loss from jars).
5. Final Cooling: Using your jar lifter, carefully remove the hot jars from the canner and place them on a clean towel on your countertop. Arrange them with adequate space between each jar to allow for even air circulation. Do not tip the jars or wipe away any excess water from the lids. Let the jars sit undisturbed for a minimum of 12 hours, or ideally 24 hours, to allow for a complete seal to form.
6. Check Seals: After the cooling period, check the lids to confirm they have sealed. A properly sealed lid will have a noticeable depression in the center and will not flex when pressed. If any lids still have a “bubble” in the center or can be pushed down, they have not sealed. These unsealed jars should be refrigerated immediately and consumed within two weeks.
7. Storage: Store properly sealed jars of caramelized onion jam in a cool, dark place, such as a pantry, for up to 18 months for optimal quality. Once a jar has been opened, it must be refrigerated and consumed within two weeks.

Altitude Adjustments for Safe Canning

While this recipe yields a delicious savory jam, for the purposes of safe water bath canning, it is categorized as a “relish.” Therefore, it adheres to the specific canning guidelines and processing timetables established for relishes. This recipe is suitable for half-pint (8-ounce) or pint (16-ounce) jars, with the canning times remaining consistent for both sizes.

• 0 to 1,000 feet above sea level – Process for 10 minutes.
• 1,001 to 6,000 feet above sea level – Process for 15 minutes.
• Above 6,000 feet above sea level – Process for 20 minutes.

Exciting Onion Jam Variations to Explore

The beauty of homemade caramelized onion jam lies in its adaptability. While the basic recipe is stellar, a wide array of spices and herbs can be introduced to impart slightly different flavor profiles and add a personal touch. Experimenting with these additions can lead to truly unique and delightful results:

• Herbal Infusions: Consider adding fresh sprigs of rosemary or thyme during the simmering phase. These herbs infuse the jam with earthy, aromatic notes. A bay leaf can also add a subtle background complexity, which you would remove before jarring.
• Spice it Up: A pinch of red pepper flakes can introduce a gentle heat, while a teaspoon of smoked paprika can add a smoky depth, especially if you’re pairing it with grilled meats. A dash of ground black pepper enhances the overall savoriness.
• Onion Type Exploration: While red onions lend a beautiful color, using sweet onions (like Vidalias) will result in an even milder, sweeter jam with less of the pungent “zing.” Conversely, stronger yellow onions will create a more robust flavor.
• Vinegar Swaps: Substituting balsamic vinegar for cider vinegar will yield a very distinct, richer, and slightly sweeter flavor profile for your jam, perfect for Italian-inspired dishes or cheese boards.
• Sweetener Alternatives: Although maple sugar is highly recommended for its unique characteristics, you can certainly experiment with brown sugar for a richer molasses note, or even regular granulated sugar for a cleaner, more straightforward sweetness. Just be mindful that the final flavor and texture might vary.
• Olive Oil Nuances: If you appreciate the complex flavors of olive oil, using a high-quality, extra virgin olive oil instead of a neutral cooking oil can impart subtle fruity and peppery undertones to your finished jam, adding another layer of sophistication.
• Bacon Onion Jam: For an ultimate indulgence, try sautéing a few strips of finely diced bacon until crispy before adding the onions. The bacon fat will add immense flavor, and the crispy bits can be stirred into the jam at the end, creating a truly irresistible bacon caramelized onion jam.

Inspiring Ways to Savor Your Caramelized Onion Jam

Caramelized onion jam is an incredibly versatile condiment that can transform countless dishes. Its sweet, savory, and tangy profile makes it a fantastic accompaniment for a wide range of meals and snacks. Here are some of my absolute favorite ways to enjoy it:

• Gourmet Burgers and Sandwiches: Elevate any burger, from beef to turkey or veggie, with a generous dollop. It’s also fantastic on chicken breast sandwiches, pork loin sandwiches, or even a simple grilled cheese, turning everyday fare into a gourmet experience.
• Charcuterie and Cheese Boards: A staple on any impressive charcuterie board, it pairs beautifully with soft cheeses like brie, goat cheese, or cream cheese, as well as harder aged cheeses. Its sweetness balances the richness of meats and cheeses.
• Grilled and Roasted Meats: Use it as a glaze for roasted chicken or pork tenderloin, or spread it generously on grilled sausages, bratwurst, or hot dogs for an unforgettable flavor boost. It’s also an excellent condiment for steak.
• Appetizers and Crostini: Create sophisticated appetizers by spreading a layer of soft cheese (like cream cheese or goat cheese) on toasted baguette slices, then topping with a spoonful of caramelized onion jam.
• Breakfast and Brunch: Try it alongside scrambled eggs, smeared on a savory waffle, or as a unique spread on toast with avocado.
• Vegetable Enhancement: It’s simply sublime with roasted red potatoes, grilled zucchini, or roasted carrots. Don’t hesitate to experiment with your favorite roasted or grilled vegetables; this jam will surely make them shine.
• Pizza and Flatbreads: Use it as a base sauce for a gourmet pizza, or as a topping along with goat cheese and fresh herbs. It also makes a tasty addition to a turkey wrap or quesadillas.
• Unexpected Pairings: Stir a spoonful into homemade mac and cheese for an incredibly rich and complex flavor. It can also be thinned slightly and used as a unique salad dressing component or a glaze for meatballs.

Really, anywhere you’d use caramelized onions, you can confidently substitute this delicious caramelized onion jam for a burst of concentrated flavor and convenience!

Other Creative Ways to Preserve Onions

If you’ve got an abundance of onions and are looking for even more innovative ways to preserve this versatile vegetable, here are a few excellent methods to consider:

• Freezing Onions: A simple and effective method for long-term storage, perfect for having pre-chopped onions ready for cooking.
• Dehydrating Onions: Creates lightweight, shelf-stable onion flakes or powder that are excellent for seasoning, soups, and stews.
• Onion Wine: An adventurous and unique way to preserve onions, transforming them into a savory fermented beverage (though perhaps not for everyone!).

5 from 5 votes

Servings:
32 servings, makes 4 half-pint (8-ounce) jelly jars

Caramelized Onion Jam

By Ashley Adamant

Caramelized onion jam is a unique savory jam that’s delicious no matter where you use it.

Prep:
20 minutes

Cook:
1 hour 15 minutes

Additional Time:
10 minutes

Total:
1 hour 45 minutes

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Equipment

• Water Bath Canner
• Large, heavy-bottomed pan or Dutch oven
• Canning funnel
• Jar lifter

Ingredients

• 1 Tbsp cooking oil, neutral (sunflower, grapeseed, or olive oil)
• 3 lbs red onions, sliced
• 1 cup maple sugar (or light brown sugar)
• 2 Tbsp bottled lemon juice
• 1½ cups cider vinegar
• 2 tsp kosher salt

Instructions

1. If canning, prepare a water bath canner, jars, and lids before beginning. If not canning, simply let it cool on the counter in jars before storing in the refrigerator.
2. Heat oil in a large, heavy-bottomed pan or Dutch oven over medium-high heat, then add the sliced onions and stir to coat.
3. Reduce the heat to very low and cook the onions for 45-50 minutes, stirring often, until softened and reduced.
4. Add maple sugar to the cooked onions and stir until the sugar is dissolved.
5. Increase the heat to medium-high and cook the onions and sugar for 3-4 minutes, stirring constantly.
6. Carefully stir in the vinegar and lemon juice, being cautious of splattering and vinegar vapor.
7. Reduce the heat to medium and add salt to the mixture.
8. Cook the onion mixture until the vinegar has reduced to a sticky syrup, about 10-12 minutes.
9. Pour or ladle the hot jam into prepared hot jars, leaving ½-inch headspace at the top of the jars.
10. Wipe the rims of the jars with a clean cloth, and apply the 2-part canning lids (finger-tight).
11. Preserve the homemade onion jam using a hot water bath canning method for 10 minutes, adjusting time if necessary for altitude (see notes).
12. After processing, turn off the heat and leave jars in the canner, uncovered, for 5 minutes. Remove the jars from the canner and let them cool for 12-24 hours. Check that the jars have sealed. Refrigerate any unsealed jars.
13. Sealed red onion jam will retain peak quality for up to 18 months stored in a cool, dry place or pantry. Refrigerate the jam once opened and use within two weeks.

Notes

Altitude Adjustments

While this definitely tastes like a savory jam, for canning purposes it’s considered a “relish” and it follows those safe canning guidelines and timetables. It can be put up in half-pint jars or pint jars, and the canning times are the same for both jar sizes.

• 0 to 1,000 feet – 10 minutes for half pints pints
• 1,001 to 6,000 feet – 15 minutes for half pints pints
• Above 6,000 feet – 20 minutes for half pints pints

Nutrition

Calories: 50kcal,
Carbohydrates: 11g,
Protein: 0.5g,
Fat: 0.5g,
Saturated Fat: 0.1g,
Polyunsaturated Fat: 0.1g,
Monounsaturated Fat: 0.3g,
Trans Fat: 0.002g,
Sodium: 148mg,
Potassium: 92mg,
Fiber: 1g,
Sugar: 8g,
Vitamin A: 1IU,
Vitamin C: 4mg,
Calcium: 17mg,
Iron: 0.2mg

Nutrition information is automatically calculated, so should only be used as an approximation.

More Savory Jam Recipes to Try

Homemade jam doesn’t always have to mean sweet, sugary spreads for your morning toast. The world of savory jams is rich with exciting possibilities, offering unique flavors that can add spice and depth to dinners, sandwiches, or snacks. If you’ve enjoyed making this caramelized onion jam, consider exploring these other fantastic savory jam recipes:

• Savory Herbal Jelly: A delicate yet flavorful jelly infused with herbs, perfect for pairing with roasted meats or artisan crackers.
• Tomato Jam: A vibrant and tangy jam that’s wonderful on burgers, sandwiches, or as an accompaniment to grilled cheese.
• Garlic Scape Jam: A pungent and sweet preserve made from the curly green shoots of garlic, ideal for charcuterie or spread on crusty bread.
• Chive Blossom Jelly: A beautifully colored and delicately flavored jelly, often with a hint of onion, perfect for spring entertaining.