4 to 5 large yellow onions (about 1 1/2 lb)
3 tbsp. butter
1/4 tsp. coarsely ground black pepper
1 tbsp. all purpose flour
3 cans (10 3/4 oz.) beef broth, undiluted
3 c. water
1 bay leaf
Salt and pepper to taste
6 to 8 slices French bread
2 tbsp. parmesan cheese
1 c. grated Swiss or Gruyere' cheese

Put thinly sliced, peeled onions in melted butter in a 4 quart sauce pan. Add ground pepper and saute' onion mixture until light golden brown, stirring frequently with a wooden spoon. Sprinkle with flour, cooking 1 minute longer after flour disappears while stirring. Add beef broth, water and bay leaf. Return to moderately high heat and bring to a boil while stirring. Reduce heat to low and cook uncovered for 30 to 40 minutes. Discard bay leaf. Spoon soup into oven proof bowls and arrange toasted French bread slices on top of soup. Sprinkle liberally with both cheeses. Place under broiler until cheese turns golden. Remove from oven and serve immediately.