Ingredients
Soup Base
- 4 large onions, thinly sliced
- 3 tablespoons butter
- 1 tablespoon olive oil
- 2 cloves garlic, minced
- 6 cups beef broth
- 1 teaspoon thyme
- 1 tablespoon flour (optional, for thickening)
- Salt and pepper to taste
Toppings
- Baguette slices
- 1 cup grated Gruyère or Swiss cheese
Instructions
- Caramelize the Onions: Melt the butter and olive oil together in a large pot over medium heat. Add the thinly sliced onions and cook slowly for 25 to 30 minutes, stirring occasionally, until they are deeply golden and caramelized to develop a rich, sweet flavor.
- Add Garlic and Flour: Stir in the minced garlic and the optional tablespoon of flour to the caramelized onions. Cook for about 1 minute to remove the raw flour taste and help thicken the soup slightly.
- Simmer with Broth and Seasoning: Pour in the beef broth and add the teaspoon of thyme along with salt and pepper to taste. Bring the mixture to a gentle simmer and cook uncovered for 15 to 20 minutes to blend the flavors.
- Prepare Cheese Toasts: While the soup simmers, toast baguette slices in the oven until crisp. Then sprinkle the toasted slices with the grated Gruyère or Swiss cheese.
- Assemble and Broil: Ladle the hot soup into oven-safe bowls. Float the cheesy baguette slices on top of the soup and place the bowls under the broiler until the cheese is melted, bubbly, and slightly browned, about 3 to 5 minutes.
Notes
- For a vegetarian version, substitute the beef broth with vegetable broth.
- Use Swiss cheese if Gruyère is unavailable, though Gruyère is traditional for its nutty flavor.
- Keep stirring the onions frequently while caramelizing to prevent burning and ensure even cooking.
- The optional flour helps thicken the soup, but can be omitted for a lighter texture.
- Prep Time: 10 minutes
- Cook Time: 45 minutes
- Category: Soup
- Method: Stovetop
- Cuisine: French
- Diet: Vegetarian
