Julia Child's French Onion Soup

Name: Julia Child's French Onion Soup
Prep time: 30 min
Cook time: 2 h
Total time: 2 h 30 min
Cuisine: European, American, Mediterranean, French
Ingredients: 5-6 cups yellow onions, thinly sliced; 1 tablespoon cooking oil; 2 tablespoons butter; 1/2 teaspoon sugar; 1 teaspoon salt; 3 tablespoons flour; 6 cups beef stock (better if homemade); 1/2 cup wine (dry white wine or dry white vermouth); 8 slices French bread, about 1-inch thick; 4 tablespoons olive oil for drizzling; Salt and pepper to taste; 2-3 tablespoons cognac; 1/2 raw yellow onion, grated; 12 ounces Swiss cheese, grated; 4 ounces parmesan cheese, grated