Parmesan Croutons (below)
2 c shredded Mozzarella cheese
¼ c butter
2 Tbsp packed brown sugar
2 tsp Worcestershire sauce
2 large onions, sliced
2 10 ½-oz cans condensed beef broth
2 soup cans water
Prepare Parmesan Croutons; set aside.
Set oven temperature to 325.
Heat butter in Dutch oven until melted. Stir in brown sugar and Worcestershire sauce. Toss onions in butter mixture.
Bake uncovered about 2 ½ hours (this is worth the wait), stirring every hour, until onions are deep, golden brown. Stir in beef broth and water. Heat to boiling over high heat.
Set oven to broil. Ladle soup into broiler-proof soup bowls, sprinkle each with a handful of Parmesan Croutons, and about ½ cup Mozzarella cheese. Place on a baking sheet and broil 2 to 3 inches from heat, until cheese is browned and bubbling. Serve immediately.
Heat oven to 400. Cut 3 slices bread into 1” cubes. Heat ¼ cup butter in 9 x 13 pan, in oven until melted. Toss bread cubes in butter until evenly coated. Sprinkle with grated parmesan cheese. Baked uncovered 10 to 15 minutes, stirring occasionally, until golden brown and crisp. I usually double this recipe because they are so delicious that we end up eating half of them before the soup is ready.