How To make Soupe a L'Oignon Au Fromage French Onion So

6 lg Onions, Thinly Sliced
1/4 c Unsalted Butter
1 tb Flour
1 1/2 qt Beef Broth
12 1/2"Slices French Bread
1/4 lb Gruyere Cheese, Grated
In a large kettle, cook the onions in the butter over moderate heat, stirring until they are golden brown. Sprinkle with flour and cook the mixture, stirring, for 3 minutes. Add the broth slowly, stir the soup constantly until it comes to a boil. Simmer, covered, for 20 minutes. Season with salt and pepper. Put 2 slices of toast in each of 6 heated bowls, top each toast with 1 Tbsp cheese and pour the soup over the toasts. Top with any remaining cheese. Run bowls under broiler about 4 inches from the flame for 3 minutes or until cheese is melted and bubbly. a 1951 Gourmet Mag. favorite.