Caramelized Onion Jam

Sweet & Savory Onion Confit

Caramelized onion jam is something I like to keep in the refrigerator because a small amount can add a lot of flavor to a simple meal.

The onions are cooked slowly with sugar, vinegar, thyme, and salt until they become soft, glossy, and deeply caramelized. I use a combination of cherry vinegar and white balsamic vinegar, which gives the onions a balance of sweetness and acidity.

This onion jam is especially good with sandwiches, burgers, steak, hot dogs, and pizza. I also like it with a simple chicken sandwich, where the sweet and tangy onions add flavor without needing a complicated sauce.

The recipe takes some time, but most of that time is simply allowing the onions to cook and rest. As they cook slowly, they become softer, darker, and more concentrated in flavor.

Slice the onions

Supplies:

• Mixing bowl medium size or tall container

• Whisk

• Spatula

• Knife

• Scale or mandoline slicer

• Mason jar

• measurement cups

• frying saucepan /grill skillet

• Stand mixer/ Electric blender or regular blender machine

Watch my YouTube video how to make onion jam here:

Lower the heat and cover

Ingredients

• 5 yellow onions

• 200g granulated sugar

• 100ml cherry vinegar

• 100ml white balsamic vinegar

• 2 sprigs fresh thyme

• 1 tsp salt

• 1 tbsp olive oil, or as needed

• 1 tbsp butter, optional

Adding herbs and wine vinegar and sugar

Prepare the Onions

Peel the onions and slice them thinly. You can also cut them into smaller pieces if you prefer a finer-textured onion jam.

Heat the olive oil and butter in a large saucepan over low heat.

Add the onions, cover, and cook gently for approximately 10 minutes, stirring occasionally, until they begin to soften.

Add the Sugar & Vinegar

Add the sugar, cherry vinegar, white balsamic vinegar, thyme, and salt.

Stir well and continue cooking over low heat for approximately 20 minutes.

The onions will become increasingly soft as the liquid begins to reduce.

Ingredients: 

• 5 yellow onions

• 200g sugar/ 1 cup sugar

• 100 ml /1/2 cup Cherry vinegar

• 100 ml/ 1/2 cup White balsamic vinegar

• 2 thyme sprigs

• 1 tsp salt

• Oil for cooking

Rest the Onion Jam

Remove the pan from the heat and allow the mixture to cool.

Let the onions rest for 4–6 hours or overnight.

This resting period is part of my method. It gives the onions time to sit in the sweet-and-sour cooking liquid before their final reduction.

Final Cooking

Return the onions to the saucepan and cook again over low heat for approximately 20 minutes, stirring occasionally.

Continue cooking until the onions are soft, translucent, glossy, and sticky, and the liquid has reduced to a jam-like consistency.

Remove the thyme sprigs.

Allow the onion jam to cool before transferring it to a clean container.

Cooking with Confidence

Use low heat. You're trying to soften and concentrate the onions gradually rather than fry them quickly.

Don't judge the texture while it's very hot. The syrup becomes thicker as it cools.

Watch closely near the end. Once most of the liquid has evaporated, the sugar can catch on the bottom of the pan much more easily.

Adjust the final reduction by appearance rather than only by time. Five onions can contain different amounts of water, so one batch may need slightly longer than another.

How I Use It

One of my favorite simple combinations is:

Chicken + caramelized onion jam + bread

But it also works beautifully with pizza.

Try it on homemade pizza: Spread a little onion jam over the pizza and pair it with goat cheese, mozzarella, or other toppings you enjoy.

Tips:

Preparation 

1. Choose a sharp knife

2. Use a cutting board with a non-slip surface

3. Refrigerate the onion for 30 minutes to reduce tear-inducing gas release

4. Peel the onion, removing the skin and trimming the ends

Slicing Techniques

1. Slice from root to tip, maintaining even pressure

2. Use a gentle, smooth motion, applying minimal pressure

3. Make parallel cuts, then slice across for uniform pieces

4. Use a mandoline or julienne slicer for precise, thin slices

Safety Tips

1. Cut away from your body

2. Keep fingers curled under and out of the knife's path

3. Use a knife with a comfortable grip

4. Avoid cutting when tired or distracted

Reducing Tears

1. Cut under cold running water

2. Use a fan or ventilation to dissipate gas

3. Cut from the root end to minimize gas release

4. Apply lemon juice or vinegar to the onion

Additional Tips

1. Use a very sharp knife to minimize cell damage and tear-inducing compounds

2. Slice onions just before using to minimize oxidation and flavor loss

3. Store sliced onions in an airtight container to preserve flavor

Some popular onion slicing methods: 

- Julienne (thin strips)

- Dice (small cubes)

- Slice (thin rounds)

- Chop (small pieces)

- Mince (finely chopped)

see my Beef stir-fry