Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   1      tablespoon    olive oil
   2      pounds        red onions -- cut crosswise
                        - into 1/2 inch thick slice
                        coarse salt
                        black pepper -- coarsely
                        - ground
   2      tablespoons   balsamic vinegar
   1      teaspoon      chopped fresh rosemary

Preparation:

Heat a clean griddle and brush with 1/2 of the oil. Brush onion slices lightly with remaining oil on both sides, season with salt and pepper and place on griddle. Grill for 3 to 5 minutes on each side, or until softened and lightly charred. Transfer onions to a bowl, drizzle with vinegar and sprinkle with rosemary. Toss to separate rings and season with more salt an pepper as needed.