Ingredients for 4 servings:
1. 2 large red onions
2. 3 tablespoons extra virgin olive oil
3. 3/4 cup balsamic vinegar
1. Preheat the oven to 425 degrees.
2. Cut the onions in half lengthwise, leaving the skins on.
3. In a 12 inch oven proof skillet, heat the oil until smoking.
4. Place 4 onion halves cut side down in the skillet.
5. Cook without moving them, over medium heat, until dark golden brown, 7 to 8 minutes.
6. Add the vinegar and place the skillet in the oven.
7. Bake until the onions are soft, 15 to 20 minutes.
8. Remove the onions from the pan immediately.
9. Place cut side up on a cool plate.
10. Pour the syrup that has formed in the pan over the onions and cool to room temperature.