1. Preheat oven to broil. Place bread on baking sheet, and cover each piece with 2 to 3 Comté slices. Broil 3 minutes 6 inches from heat source or until cheese melts and is bubbly and brown.
2. Toss onion and next 5 ingredients gently with Balsamic Vinaigrette.
3. Sauté mushrooms in oil 5 minutes or until tender. Top salad with mushrooms and bread rounds. Serve while cheese and mushrooms are warm.