8 cups thinly sliced sweet yellow onions (approximately 4 large onions)
2 tablespoons olive oil
2 tablespoons fresh thyme
2 tablespoons maple syrup
2 tablespoons balsamic vinegar
1/2 teaspoon salt
Place the sliced onions in a large (4-quart) crockpot and add the remaining ingredients. Toss to coat. Cover and set the cooker on high. Cook for 4 hours, opening halfway to stir and re-cover. At 4 hours, uncover and continue cooking on high for 2 more hours. Stir occasionally, until the mixture is thick and the liquids are syrupy.
For a faster method that requires frequent stirring, you can also move the onions to a 2-quart saucepan after 4 hours in the crockpot. Place the pan on the stove over medium-high heat and stir frequently as the mixture comes to a boil. Cook, stirring often, until the mixture is thick and the liquids are syrupy, about 10 minutes. Transfer onion jam to a jar; it will keep refrigerated for up to two weeks.
Tips: Life is just better with condiments — especially exciting, homemade condiments that can be eaten by the spoonful alongside meats, vegetables and grains, or added to sandwiches and pizza. Vary the flavor of this onion jam by adding rosemary or sage instead of (or in addition to) the thyme.