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Caramelized Onion Jam

A deeply sweet and glossy onion jam with concentrated caramel flavors, achieved through low and slow cooking. This fancy-tasting condiment requires just five simple ingredients and transforms humble onions into a restaurant-quality spread perfect for bread, cheese, meats, or even vanilla ice cream.
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Prep Time 10 minutes
Cook Time 45 minutes
Total Time 55 minutes
Servings: 8 servings
Course: Appetizer, Condiment
Cuisine: French
Calories: 45
Ingredients Equipment Method Notes

Ingredients
  

Main
  • 2 pounds yellow onions about 6 medium onions, peeled and sliced thin
  • 3 tablespoons unsalted butter
  • 1 teaspoon salt
  • 1/4 teaspoon black pepper
  • 2 tablespoons balsamic vinegar
Optional
  • 1 tablespoon honey or brown sugar for extra depth
  • 1/2 teaspoon fresh thyme leaves

Equipment

  • Large heavy-bottomed pot or Dutch oven (at least 3-quart capacity)
  • Sharp chef's knife
  • Cutting board
  • Wooden spoon or silicone spatula
  • Measuring spoons and cups
  • Small glass jars for storage

Method
 

  1. Slice your onions thinly, about 1/4 inch thick, keeping them mostly consistent in size so they cook evenly.
  2. Place your pot on the stove over medium heat and add the butter, letting it melt completely and coat the bottom evenly.
  3. Add all sliced onions into the pot along with the salt, stirring well to coat everything with butter.
  4. Cook at medium heat for 15 minutes, stirring occasionally, letting the onions soften and release their moisture as the pot becomes steamy.
  5. Reduce heat to medium-low and cook for 20 minutes, stirring every few minutes, allowing the onions to brown gradually without burning until they transition from translucent to golden.
  6. Continue cooking, stirring every 5 minutes or so, scraping any browned bits from the bottom of the pot and mixing them back in until the entire mass turns a deep mahogany color and takes on a jam-like consistency.
  7. Add balsamic vinegar, black pepper, and optional honey and thyme if using, stirring well to combine.
  8. Cook for a final 2 minutes to meld the flavors, then taste and adjust salt or vinegar as needed.
  9. Let cool completely before transferring to airtight glass containers for storage.

Notes

Don't rush the caramelization process by turning up the heat, or your jam will taste harsh and burnt instead of sweet and complex. If your jam seems dry before reaching deep color, add a splash of water or stock. For vegan version, swap butter for olive oil. Store in refrigerator for up to 3 weeks or freeze in ice cube trays for up to 3 months.