French onion soup 8 cups fonds blanc 3 cups onion, sliced 2 tbsp. butter 8 tbsp. mixed grated Gruyere and Parmesan cheese salt and pepper to taste 1 baguette Melt the butter on low heat in a large saucepan. Add the onion, and cook for 30-40 minutes, stirring often, until the onions are soft and golden brown. Add the fonds blanc, and simmer for 30 minutes. Add salt and pepper to taste. In a 375 F oven place 16 1/2-inch slices of bread, cut into 1-inch pieces. Bake until golden brown (5-8 mins).  Put the soup into individual serving dishes, top with the croutons and 1 heaping tbsp. cheese each.  Brown the cheese under a broiler and serve immediately.