Here's the Martha method. I also like cutting them in wedges & adding them to mashed potatoes. One of my fav comfort food recipes is a carrot/potato whip -- mashed potatoes & mashed carrots combined & the caramelized onions mixed in & seasoned to taste. Also like them on liver.
Makes about 1 cup
These browned, sweet onions make a wonderful topping for pizza, burgers, sandwiches, and grilled meats.
1 tablespoon unsalted butter
1 tablespoon olive oil
2 medium onions (about 1 1/2 pounds), sliced into 1/8-inch rounds
1 teaspoon sugar
1/2 teaspoon salt
1/4 teaspoon freshly ground black pepper
2 tablespoons fresh thyme leaves or 1 teaspoon dried thyme (optional)
Heat butter and oil in a medium skillet over medium-low heat. Add onions, and cook until they begin to soften, stirring occasionally, about 15 minutes. Add sugar, salt, and pepper; raise heat slightly, and cook until golden brown, stirring occasionally, 30 to 35 minutes. Stir in thyme, if using, and serve warm.