- 2 onions, thinly sliced
- 1/4 cup butter
- 2 tablespoons all-purpose flour
- 2 (10.5 ounce) cans beef broth
- 2 1/2 cups water
- 6 slices French bread, toasted
- 1/2 cup grated Parmesan cheese
- 1/2 cup shredded Swiss cheese
Preheat oven to 425 degrees F(220 degrees C). Separate sliced onion into single rings.
In a medium sauce pan saute onions in butter until soft, approximately 20 minutes. Stir in flour and gradually add broth and water. Bring to a boil and simmer for 20 minutes.
Meanwhile, toast French bread slices.
Place toasted bread into soup bowls. Pour soup mixture over bread and sprinkle with Parmesan and Swiss cheese. Bake for 10 minutes.