Balsamic Onions

• 4 tablespoons olive oil
• 2 large onions, thinly sliced
• ⅓ cup

Heat the oil in a medium heavy-bottomed skillet over medium-high heat. Add the onions and stir for 5 minutes, or until just starting to caramelize. Add the sugar and stir until dissolved. Add the vinegar and cook over low heat for 25-30 minutes, stirring occasionally, or until the mixture is a jam-like consistency.