Ingredients

• 2 tablespoons extra-virgin olive oil
• 1 large red onion, halved and thinly sliced
• Salt and pepper
• 1 rosemary sprig
• 1 tablespoon balsamic vinegar
• 2 teaspoons soy sauce

Instructions

1. In a large skillet, heat the olive oil. Add the onions, season lightly with salt and pepper and cook over moderate heat until they start to soften, about 5 minutes. Add the rosemary and continue cooking the onions until very soft and just starting to brown, about 10 minutes longer.
2. Add the balsamic vinegar and soy sauce and cook just until the liquid is mostly evaporated, about 1 minute. Remove the rosemary sprig and serve.