Onion Jam

Preparation info

  • Difficulty


  • Makes

    1 cup

Appears in

Good to the Grain

By Kim Boyce

Published 2010

  • About

I’m always surprised by caramelized onions, a rich jam made by simply cooking down slices of this kitchen staple. How can something so humble become so rich in flavor? As the onions cook, they condense from their pungent raw state to a thick, sweet spread. Don’t be alarmed at the volume of raw onions in your pot—as they cook, they reduce to a remarkably small amount of jam. If you have a big pot, you may even want to double the recipe.


  • 2 pounds yellow onions, about cups sliced
  • 1 tablespoon olive oil
  • 1 teaspoon kosher salt
  • ½ teaspoon freshly ground black pepper, or to taste
  • 1 teaspoon red wine vinegar


  1. Cut the stem ends off the onions. Slice each onion in half through the root end. Lay each onion half cut side down and slice it, toward the root, into slices about ¼ inch thick.
  2. Heat a 5- to 7-quart heavy-bottomed pot over a medium-high flame. Add the olive oil and heat until it’s shimmering. Add the onions, salt, and pepper and stir to coat the onions with the oil. Sauté the onions for 10 to 15 minutes, stirring occasionally, until the onions have lost their gloss, the bottom of the pan is getting dark in areas, and the edges of the onions are beginning to brown. Turn the flame to low, cover the pot, and cook for 20 minutes.
  3. Uncover the pan, stir the onions, scrape any dark flavorful bits from the bottom of the pan, and continue to cook, uncovered, for 1 hour more. Stir the onions occasionally, especially towards the end of the cooking time, to prevent burning. The onions are ready when the liquid has evaporated and the onions are dark, translucent, and jammy. Stir in the vinegar and allow to cool. The onion jam will keep in the refrigerator for 2 weeks, or in the freezer for 1 month.