4 lg. white onions, sliced (about 1 1/2-2 lb.)
4 tbsp. butter
2 tbsp. flour
3 (13 3/4 oz.) cans beef broth
1/2 tsp. salt
1/4 tsp. pepper
1/2 c. dry white wine
8 (1/2") thick slices French bread, toasted
8 slices Gruyere or Swiss cheese

Saute onions in butter in a heavy 4 quart saucepan over medium heat, stirring often, until golden, about 20-30 minutes. Stir in flour; cook 1 minute. Add beef broth, wine, salt and pepper. Heat to boiling. Reduce heat and simmer, partially covered, 30 minutes.

Heat broiler. Ladle soup into 4 (12 or 16 ounce) oven proof soup bowls and place on a baking sheet. Add 2 slices toasted bread to each, and cover with 2 slices cheese. Broil 6 inches from heat, until cheese is bubbly brown and forms a crust. Place bowls on plates and serve at once.