Baked French Onion Soup

Makes  great side dish to any  meal. 6 servings

Ingredients:
3 medium sweet onions, sliced
3 tablespoons butter
4 cups beef broth
1 teaspoon Worcestershire   sauce                                                                                                            
1 cup shredded Mozzarella cheese  
6 slices French bread, about 1/2-inch in thickness

Instructions:
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 soup mixture into a  casserole dish.
Toast the slices of bread on both sides at 350 degrees until golden and place toasted bread in a single layer on top of onion soup.
Cover bread with a thick layer of the shredded mozzarella and top.
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.