This 6-ingredient caramelized onion jam is rich, sweet, jammy, and packed with flavor (and no pectin!) – perfect for enjoying with a cheese board, over burgers, at Thanksgiving, in a grilled cheese, and more!

While I’ve shared recipes for strawberry jam, rose petal jam, and fig jam, I’m heading a little more savory this time around. This sweet onion jam recipe is wonderfully sweet and savory, like caramelized onions but even better thanks to the addition of balsamic vinegar, sugar, and thyme.

This onion condiment requires no pectin or complicated jam-making techniques. You can also swap out the vinegar, the sugar, and the herbs, or add extra ingredients to it. Keep reading for tons of my favorite recommendations. Once ready, these onion preserves are a super versatile addition to party spreads, cheeseboards, appetizers, and mains!

For more jam recipes, you might enjoy my pumpkin jam, raspberry jam, blackberry jam, and ginger marmalade!

What is Onion Jam?

Onion jam (sometimes called onion jelly or caramelized onion jam) is a simple combination of onions, sugar, and vinegar, with your choice of herbs and other aromatics cooked down into a sticky, sweet, jam-like consistency. Unlike fruit jam, the diced onion is left intact, and the mixture is pectin-free.

For this recipe, the sweet and savory onion flavor is packed with tons of depth thanks to the addition of balsamic vinegar, black pepper, thyme, and bay leaves.

The Ingredients

This simple balsamic onion jam recipe requires just six pantry-friendly ingredients.

• Onions: I recommend using sweet onion or yellow onions. I prefer sweet onion jam, though.

• Sugar: I used unrefined cane sugar. You could use another type of sugar, like coconut sugar or brown sugar, though the flavor will vary.
• Olive oil: I used extra virgin olive oil, but feel free to use another neutral cooking oil like avocado oil.
• Vinegar: I use balsamic vinegar, which is typical in an onion jam recipe. However, you could also experiment with red wine vinegar, white wine vinegar, or even apple cider vinegar.
• Salt: Season to taste.
• Herbs: I used fresh thyme and a bay leaf.

Optional Add-ins and Variations

• Butter: For a richer onion jam, replace some olive oil with butter.
• Rosemary: Add a single sprig (around 3-4 inches long) to the saucepan. Remove it before jarring the balsamic onion jam.
• Oregano: A pinch of dried oregano would pair well.
• Lemon: You can add lemon juice and zest to brighten the flavor.
• Clove: Add a pinch of ground clove for depth.
• Worcestershire sauce: A splash will add further depth.
• Allspice leaves: You could use this instead of a bay leaf.
• Ginger: Use finely grated ginger. I recommend ¼ tsp to begin and increase if you prefer a more robust flavor.
• Garlic: I haven’t tried this, but I imagine adding a small amount of roasted garlic to the onion jam recipe would taste delicious.
• Alcohol: Add a splash of port or bourbon towards the end.
• Spice: Add a pinch of red pepper flakes OR some finely chopped chilies.
• Mustard: A small amount of Dijon mustard helps to add depth and a slight heat.

How to Make Onion Jam (Onion Preserves)

Step 1: Sauté the Onions

First, peel and dice (or slice) the onions.

Then, in a large heavy-bottomed pot/skillet, add the oil and heat over medium-high heat.

Once hot, add the onions to the pan and cook for 15 minutes, stirring often, until the onions are tender and golden-brown.

Step 2: Add the Remaining Ingredients

Reduce the heat to low, add the thyme and bay leaf, and cook for 3-5 minutes.

Then, sprinkle the sugar over the onions, leaving it to cook for 5 minutes, untouched. The aim is for it to melt over the onions without stirring.

If you stir the sugar in with the onions, it can seize into clumps. While it’s possible to melt it back down again, the process takes longer and is annoying.

Increase the heat to high and cook for 5 minutes, or until the sugar caramelizes and turns golden-brown, without stirring.

To avoid the caramel burning, it’s important to watch the pan fairly closely at this point so you can reduce the heat if needed.  

Next, add the balsamic vinegar and stir, then simmer on low for 5 minutes. During this time, the balsamic onion jam mixture should thicken, though feel free to simmer it slightly longer if needed.

It’s ready when you draw your spoon across the bottom of the pan, and it leaves a clear trail for several seconds.

Finally, remove the herbs from the pan, taste, and season the sweet onion jam. Allow it to cool before transferring it to a sterile jar to store.

Storage Instructions

Storing: Store the balsamic onion jam in a sterilized jar in the fridge for 7-10 days.

Alternatively, transfer it to the freezer for 2-3 months (in a jar with 1-inch headspace or in portions in an ice cube tray).

How to Serve Onion Jam?

To say that there are many ways to enjoy this onion jam would be a massive understatement. Here are just a few of my top picks:

You should enjoy this sweet onion jam at room temperature or warm (not chilled) for the best flavor and texture.

• As part of a cheese platter/charcuterie board with crackers and crusty bread.
• Spread over bagels, toast, simit, ciabatta, avocado toast, etc.
• Spread over a grilled cheese sandwich or other sandwiches and wraps
• It pairs amazingly with goat cheese – in salads, over pizza, a flatbread, a focaccia topping, etc. Or you can top baked brie or camembert at Christmas.
• To top a burger or hotdogs/sausage sandiwches – like this black bean burger or a halloumi burger.
• Use as a pizza topping.
• To dollop over cooked salmon, roasted chicken and other poultry, steak, lamb chops, and even tofu!
• Slather over a scone with cheese.
• Use to top tomato soup or toss into pasta (warm or a pasta salad).
• Serve with boiled potatoes. Enjoy with vegetable fritters as well as tarts and quiches.

Let me know in the comments how you best enjoy this caramelized onion jam.

FAQs

Recipe Tips and Notes

• Adjust the heat if necessary: If it looks to be cooking too quickly, then reduce the heat slightly. You don’t want to burn the onions or the sugar caramel.
• Time hack: Cut down on onion dicing time by using a food chopper to do the job. Just peel and slice them in half, then let the chopper do the work.
• Slice the onions evenly: This will ensure they cook evenly on the stovetop.
• If the onion jam is too runny: This may be the case if you’ve reduced or substituted the sugar. You could add some cornstarch slurry or pectin if preferred.
• For more flavor: For a more “caramelized onion” jam, I recommend fully caramelizing the onions before adding the herbs and sugar and continuing with the recipe.
• Adjust the texture: Traditional onion jam has the texture of the diced onion. If you want something smoother, feel free to use an immersion blender/blender to adjust it to your desired texture and consistency.
• Make sure to use sterilized jars: Whether or not you plan on water bath canning the jam, ensure you use sterilized jars for the longest shelf life. Wash them in hot, soapy water, then rinse and transfer to an oven (minus rubber and other non-heat-proof parts) at 325ºF/160ºC for 10-15 minutes.

More Simple Onion Recipes

• How to caramelize onions
• Simple roasted onions
• Crispy onions
• How to make onion powder
• How to make pickled red onions
• Homemade onion flakes
• Vegetarian French onion soup

If you try this balsamic onion jam recipe, I’d love to hear your thoughts/questions below. Also, I’d appreciate a recipe card rating below, and feel free to tag me in your recipe recreations on Instagram @Alphafoodie!