Best Easy French Onion Soup Recipe Ever

Name: Best Easy French Onion Soup Recipe Ever
Cuisine: European, Mediterranean, French
Ingredients: 6 large yellow onions, thinly sliced; 3 tablespoons butter; 1 tablespoon olive oil; 1 teaspoon sugar; 8 cups beef broth; 1 cup dry white wine (optional but lovely); 1 teaspoon thyme; 1 baguette or other crusty bread, sliced; 1½ cups grated Gruyère cheese; Salt and pepper