- 1 tablespoon extra-virgin olive oil
- 2 pounds yellow onions, halved lengthwise and cut crosswise into slices 1/4-inch thick
- 2 teaspoons minced fresh rosemary, plus sprigs for garnish
- 1 bay leaf
- 1/4 cup vegetable stock, broth or dry white wine
- 1/2 cup balsamic vinegar
- 1/4 teaspoon salt
- 1/2 teaspoon freshly ground black pepper
Add the vegetable stock to the pan and bring to a simmer. Cook until the stock evaporates completely, about 5 minutes. Add the vinegar and simmer until the liquid is completely absorbed, about 5 minutes longer. Season with the salt and pepper.
Transfer to a warmed serving dish and garnish with the rosemary sprigs. Serve immediately.