Although it may look like a pile of caramelized onions, slowly reduced red wine and balsamic vinegar make this sweet, fruity, and tart onion jam so much more.
- 2 tablespoons olive oil
- 2 pounds red onions, halved and thinly sliced
- 1 cup dry red wine
- 1/3 cup light brown sugar
- 1 tablespoon chopped fresh thyme
- 2 tablespoons balsamic vinegar
- 1/2 teaspoon Kosher salt, plus more to taste
- 1/2 teaspoon freshly ground black pepper, plus more to taste
Heat olive oil in a medium skillet over medium heat until shimmering. Add onions and cook until softened and just translucent, 8 to 10 minutes, stirring occasionally.
Add in wine, sugar, thyme, vinegar, and salt. Bring to a boil, then reduce heat low, and let simmer until liquid thickens and becomes syrupy, about 1 hour, stirring occasionally. Season with additional salt and pepper to taste. Transfer onion jam to a bowl and let cool, then serve or store in an airtight container in the refrigerator for up to 2 weeks, letting onion jam return to room temperature before using.