Ingredients
Sauce and Soup Base
- 6 cups thinly sliced onions
- 2 tablespoons butter
- 2 tablespoons olive oil
- 6 sprigs fresh thyme
- 1 bay leaf
- ½ cup white wine
- 4 cups high-quality beef broth
- salt and pepper to taste
For Serving
- 4 slices baguette, toasted
- 1 ½ cups grated Gruyere or similar cheese
Instructions
- Caramelize the Onions: In a large skillet with high sides, heat the butter and olive oil over medium heat. Add the thinly sliced onions along with thyme leaves stripped from the sprigs and the bay leaf. Cook the onions on low heat, stirring every 10 minutes to prevent sticking, until they become deeply caramelized and golden brown. This step takes about 45 minutes and is critical for developing the soup’s rich, sweet flavor. Add a teaspoon of salt during this process to help draw moisture from the onions.
- Deglaze and Simmer: Once the onions have reached a deep caramel color, pour in the white wine to deglaze the pan, scraping up any browned bits. Increase the heat to bring the mixture to a boil. Then add the beef broth and bring the soup back to a boil before reducing heat to let it simmer gently. Adjust seasoning with salt and pepper to taste while the soup simmers as you prepare for broiling.
- Prepare for Broiling: Preheat your broiler. Ladle the hot soup into four oven-safe bowls. Place a toasted baguette slice on top of each bowl of soup. Sprinkle the grated Gruyere cheese evenly over each baguette slice, ensuring a generous layer of cheese for a creamy, melty topping.
- Broil the Soup: Place the bowls under the preheated broiler and broil for about 3 to 5 minutes, or until the cheese on each bowl is melted, bubbly, and golden brown. Watch carefully to prevent burning.
- Garnish and Serve: Remove the bowls from the oven carefully. Garnish with additional fresh thyme leaves if desired. Serve the soup immediately while hot and enjoy the comforting, flavorful experience of classic French onion soup.
Notes
- Use a heavy-bottomed skillet with high sides to prevent burning the onions during caramelization.
- Low and slow caramelization is key; rushing this step can result in bitter onions.
- To save time, you can use pre-sliced onions, but fresh slicing yields better texture.
- Gruyere cheese is traditional, but Swiss or Emmental can be good substitutes.
- Use good quality beef broth for richer flavor; homemade broth works best.
- Keep a close eye when broiling to avoid burning the cheese topping.
- Prep Time: 15 minutes
- Cook Time: 1 hour 30 minutes
- Category: Soup
- Method: Stovetop
- Cuisine: French