There’s something utterly magical about caramelized onion jam—its rich, deep flavor that dances perfectly between sweet and savory. This jam isn’t just any condiment; it’s a healthy comfort food essential that elevates everything from sandwiches to cheese boards. Whether you’re looking for a delicious addition to your easy weeknight dinners or a gourmet touch for your budget-friendly recipes, this jam fits effortlessly into any meal plan. Plus, it’s an excellent choice for those following a keto meal plan or anyone craving a high protein meal with extra flavor on the side.
The beauty of this recipe is in its simplicity—just a handful of ingredients and some slow, patient cooking. The result? A luscious, thick spread bursting with umami, sweetness, and just a hint of tang. Trust me, once you’ve tasted this, you’ll want to add it to your best dinner prep meals and keep a jar ready for whenever the craving hits.
Why You’ll Love This Recipe
You’ll adore this caramelized onion jam because it turns the humble onion into something truly special. It’s not just about taste; it’s about texture too—the silky softness of the onions, the glossy sheen, and that perfect jam-like consistency that spreads smoothly on anything. It’s incredibly versatile and so easy to make at home.
This jam is naturally gluten-free and vegetarian, fitting nicely into healthy boxed meals or meal prep microwave lunches for a flavorful boost. Plus, it keeps well in the fridge or freezer, making it a convenient addition to meal planning chicken or any protein-packed dish.
What Makes This Recipe Special?
What sets this jam apart is the slow caramelization process. Taking your time to cook the onions low and slow lets their natural sugars develop fully, creating that irresistible depth of flavor. Adding balsamic vinegar introduces a bright acidity that balances the sweetness beautifully, making the jam perfect for spreading or dipping.
You can tweak this recipe to suit your tastes or dietary goals, whether you want to add fresh herbs for an herbal note or swap in maple syrup for a natural sweetener. It’s also a wonderful base to experiment with if you’re into high macro meals or need a condiment that fits into a protein eating plan.
Ingredients
- 4 large yellow onions, thinly sliced (about 800g)
- 2 tbsp olive oil
- 2 tbsp unsalted butter
- 2 tbsp brown sugar
- 3 tbsp balsamic vinegar
- 1 tsp fresh thyme leaves (or ½ tsp dried thyme)
- ½ tsp kosher salt (adjust to taste)
- ¼ tsp freshly ground black pepper
- Optional: pinch of red pepper flakes or splash of port/wine for depth
How to Make It Step-by-Step
- Prepare your onions: Peel and thinly slice your onions evenly. Uniform slices ensure they cook at the same rate and caramelize beautifully.
- Heat the fats: In a large skillet over medium heat, melt the olive oil and butter together. The combination adds richness and helps achieve that silky texture.
- Cook the onions: Add the sliced onions and stir to coat them in the oil and butter. Cook for about 5 minutes until they start to soften.
- Slow caramelization: Reduce the heat to medium-low. Continue cooking, stirring occasionally, for 25 to 30 minutes. Adjust the heat as needed to prevent burning—slow and steady wins the flavor race here.
- Add sugar and thyme: Sprinkle in the brown sugar and fresh thyme. Stir well and cook for another 2 minutes, allowing the sugar to caramelize and deepen the flavor.
- Add vinegar: Pour in the balsamic vinegar (and optional splash of wine or port). Stir and simmer for 3 to 5 minutes until the mixture thickens to a jammy consistency.
- Season and finish: Add salt, pepper, and red pepper flakes if desired. Taste and adjust seasoning.
- Cool and store: Remove from heat and let cool to room temperature. Transfer to clean jars and store in the fridge for up to two weeks.
Tips for Best Results
- Be patient! Caramelizing onions takes time, but rushing will lead to uneven cooking or burnt bits.
- Stir occasionally, scraping the pan’s bottom to prevent sticking and ensure even browning.
- Use a heavy-bottomed skillet to distribute heat evenly.
- Cooling fully before sealing jars helps preserve the jam’s freshness.
- For easy high protein high calorie meals, serve alongside roasted chicken or steak.
Ingredient Substitutions & Variations
- Swap brown sugar for maple syrup or honey for a different sweetness profile.
- Add finely chopped garlic or shallots during caramelization for extra depth.
- Use apple cider vinegar or white balsamic for a lighter, fruitier tang.
- Mix in dried figs or cranberries for a richer, fruit-forward version.
- Try red onions for a deeper color and slightly different flavor.
- Add a pinch of chili flakes for a high protein keto meal plan with a spicy kick.
Serving Suggestions
Caramelized onion jam is a flavor powerhouse that complements countless dishes. Here are some ideas:
- Spread on toasted sourdough for an elevated breakfast or full English breakfast twist.
- Add to grilled cheese sandwiches or paninis for easy weeknight dinners.
- Dollop on burgers or veggie burgers as a sweet-savory topping.
- Serve alongside cheeses on a charcuterie board for an elegant appetizer.
- Mix into mashed potatoes or risotto for healthy comfort food with a gourmet touch.
Pairing Ideas (Drinks, Sides, etc.)
- Pair with a glass of medium-bodied red wine or sparkling water with lemon for a refreshing contrast.
- Serve with crusty bread, roasted nuts, or fresh fruit slices for a balanced cheese platter.
- Add to meal prep microwave lunches with roasted vegetables and quinoa for a complete meal.
- Compliment with light salads featuring tangy vinaigrettes to balance richness.
How to Store and Reheat Leftovers
- Store jam in an airtight container in the fridge for up to 2-4 weeks.
- Freeze in ice cube trays or small portions for up to 6 months.
- Reheat gently on the stovetop or microwave before serving. Avoid overheating to keep the jam’s silky texture.
- For long-term storage, consider proper canning methods to keep the jam shelf-stable.
Make-Ahead and Freezer Tips
- Make a big batch ahead and portion into small containers for quick additions to premade lunch meals or no prep healthy lunches.
- Freeze individual servings to easily thaw and add to prepared meals for two or larger family dishes.
- This jam keeps well in the fridge, making it perfect for healthy meal plans for two or singles who like to batch cook.
Common Mistakes to Avoid
- Cooking the onions too quickly can burn them and ruin the flavor. Always keep the heat medium-low for best caramelization.
- Not stirring enough may cause uneven browning or sticking.
- Adding vinegar too early can prevent proper caramelization; wait until onions are deeply golden.
- Overcrowding the pan leads to steaming, not caramelizing—use a large skillet.
Frequently Asked Questions (FAQ)
What’s the difference between caramelized onions and onion jam?
Caramelized onions are slow-cooked until soft and brown. Onion jam is caramelized onions further reduced with sugar and vinegar until thick and spreadable.
Can I freeze onion jam?
Yes! Freeze in small portions for up to 6 months.
What kind of onions work best?
Yellow or sweet onions provide a perfect balance of natural sugars and flavor.
Is this recipe gluten-free?
Absolutely, as long as your vinegar and other ingredients are gluten-free.
Can I make it spicy?
Definitely—add chili flakes or cayenne for a little heat.
Cooking Tools You’ll Need
- Large heavy-bottomed skillet or sauté pan
- Sharp chef’s knife
- Cutting board
- Wooden spoon or heat-resistant spatula
- Measuring spoons and cups
- Airtight containers or glass jars for storage
Caramelized onion jam is one of those easy high protein high calorie meals enhancers that brings so much flavor and richness to the table. It’s a must-have in your kitchen, perfect for everything from budget-friendly recipes to meal prep microwave lunches that need a gourmet boost. Make a batch today, and watch how it transforms your meals.
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Caramelized Onion Jam
Ingredients
- 4 large yellow onions, thinly sliced
- 2 tablespoons olive oil
- 2 tablespoons unsalted butter
- 2 tablespoons brown sugar
- 3 tablespoons balsamic vinegar
- 1 teaspoon fresh thyme leaves (or 1/2 tsp dried thyme)
- 0.5 teaspoon kosher salt
- 0.25 teaspoon freshly ground black pepper
- optional pinch of red pepper flakes or splash of port/wine
Instructions
- Heat olive oil and butter in a large skillet over medium heat until melted.
- Add the thinly sliced onions and stir to coat them in the oil and butter.
- Cook the onions over medium-low heat, stirring occasionally, for 25–30 minutes until they become deep golden and caramelized. Adjust heat as needed to prevent burning.
- Stir in the brown sugar and thyme, cooking for another 2 minutes to caramelize the sugar.
- Add the balsamic vinegar and optional splash of port or wine. Simmer for 3–5 minutes until the mixture thickens to a jam-like consistency.
- Season with kosher salt, black pepper, and red pepper flakes if using. Taste and adjust seasoning.
- Remove from heat and let cool to room temperature before transferring to a clean jar or airtight container.
