Preheat your oven to 350ºF. Pour soup into six 8 ounce ovenproof serving bowls or soup crocks. Top with cheese toasts from French Onion Soup recipe. Arrange the mozzarella or Gruyere cheese over tops of bowls to cover entire opening. Sprinkle Parmesan cheese over mozzarella. Put soup bowls on a jelly roll pan. Bake for 15 - 20 minutes or until the soup is very hot and the cheese is lightly browned. Allow additional cooking time if the soup has been chilled

This great recipe came from The Art of Cooking for the Diabetic