Rich and Simple French Onion Soup

I LOVE french onion soup!! This recipe is as good or better than any resturant!!

1/4 c. unsalted butter
2 Tbs. olive oil
4 c. sliced onions
4 ( 10.5 oz) cans beef broth
1 tsp. dried thyme
salt and pepper to taste
4 slices French bread
4 slices provolone cheese
2 slices swiss cheese, diced
1/4 c. grated parmesan cheese

Melt butter with olive oil in an 8 qt. stock pot on medium heat. Add onions and continually stir until tender and translucent. Do not brown the onions. Add broth and thyme. Season with salt and pepper, and simmer for 30 minutes. Heat oven broiler. Ladle soup into oven safe serving bowls and place one slice of bread on top of each. On top of the bread put a slice of provolone, 1/2 slice diced swiss cheese, and 1 tablespoon Parmesan cheese. Place bowls on a cookie sheet and broil in the oven until cheese bubbles and browns slightly. I prefer to toast the bread in the oven before putting in on the soup or toast the bread, then put the cheese on top and broil it until the cheese is melted and then put it in the soup. (If you like garlic I have cut a clove of garlic and lightly rubbed it over the toasted bread before you cover it with cheese) Makes 4-6 servings.