Make your parmesan croutons by preheating the oven to 400 deg. Slice french bread to make 12- 1" slices. Then take those slices and roughly chop into bite size pieces. Place 1st butter in a 13 x 9 pan and let melt in oven, but watch carefully so that it does not burn. When butter has melted, add french bread pieces and toss around to coat with butter. Sprinkle with parmesan cheese and cook for 10-15 minutes or until golden and crisp. Remove parmesan croutons and set aside.

Reduce the oven to 325 degrees. Slice onions and set aside. Take 2nd butter and melt in a large pot over medium heat on the stove, being careful again not to burn the butter. Add sliced onions, sugar, worcestershire sauce, thyme and garlic. Saute onions for several minutes until slightly softened. Transfer pot to oven and bake at 325 degrees for 2 hours, stirring approximately every 30 minutes.

Remove from oven and place back on stove over medium heat. Add broth and wine, heat to boiling and then reduce heat to low and cook for another 5 minutes.

Ladle soup into oven-proof bowls, making sure that all bowls get equal amount of onions. Top each bowl with 1/4 of the croutons and 1/2 cup of mozzarella cheese. Transfer bowls to a cookie sheet and broil in oven for 2-3 minutes or until tops are golden and cheese is melted.