1/4 c butter
4 cups thinly sliced onion
4 cans (10.5 oz size) condensed beef broth, undiluted
4 to 6 slices French bread, 1 inch thick
1/2 lb grated Swiss cheese
2 Tb grated Parmesan cheese

In butter in a large skillet, saute onion until golden but not browned - about 8 minutes.

In a medium saucepan, combine beef broth and sauteed onion; bring to boiling. Reduced heat; simmer, covered, 30 minutes.

Meanwhile, in broiler, toast French bread on both sides. Sprinkle each slice with grated cheese, dividing evenly. Broil just until cheese is bubbly - about 1 minute. Cut bread up into bite size pieces.

To serve: Pour hot soup into tureen or individual soup bowls. Float toast pieces on top. Cover with a mound of Swiss cheese. Cook under the broiler until cheese melts and starts to brown.

Makes 4 to 6 servings.

Flavor is enhanced if soup is refrigerated, covered overnight and re-heated at serving time.