Peal and cut lengthwise once, then cut crosswise into slices 1/4-inch thick:

      2 pound yellow onions

Heat a large skillet and saute:

      1 tablespoon extra-virgin olive oil
      all the sliced oinons
      2 teaspoons minced fresh rosemary
      1 bay leaf

Reduce the heat, cover tightly, stirring occasionally, cook until golden, about 30 minutes.

Add and cook until stock evaporates completey, about 5 minutes:

      1/4 cup vegetable stock, broth or dry white wine

Add and simmer until the liquid is completely absorbed, about 5 minutes longer.

      1/2 cup balsamic vinegar
      1/2 teaspoon freshly ground black pepper
      1/4 teaspoon salt

Transfer to a warmed serving dish and garnish with the rosemary sprigs.