Ingredients: 1/2 cup butter (unsalted if you have it) 2 Tablespoons olive oil 4 cups sliced onion 4 cans beef broth (10.5 ounce size) 2 Tablespoons dry sherry or red wine 1 teaspoon dried thyme Salt and pepper to taste 4 slices French bread, toasted firm 4 slices provolone 2 slices Swiss cheese 1/4 cup…