- Servings: 6
- Prep Time: 10 minutes
- Cook Time: 1 hour 30 minutes
- 3 medium sweet onions, sliced
- 3 tablespoons butter
- 4 cups beef broth
- 1 teaspoon Worcestershire sauce
- Approximately 6-8 slices French bread, about 1/2-inch in thickness
- 1 cup Mozzarella cheese
- 1/2 cup grated Parmesan cheese
- Melt butter in a large saucepan over low heat. Add onions and cover. Cook for about 30 minutes, stirring occasionally.
- Add the beef broth and the Worcestershire sauce. Heat the broth mixture until it boils.
- Reduce heat to low. All to simmer, uncovered, for about 30 minutes. The broth will reduce.
- Pour onion and broth mixture into a greased casserole dish.
- Lightly toast the slices of bread. Place toasted bread in a single layer on top of onion/broth mixture.
- Cover bread with a thick layer of the shredded mozzarella and top with grated Parmesan.
- Place dish under the broiler, watching carefully. Broil until the cheese melts and begins to brown and bubble.
- Let cool for 2-3 minutes. Serve immediately.