Ingredients
Scale
- 4 large yellow onions, thinly sliced
- 3 tablespoons unsalted butter
- 1 tablespoon olive oil
- 1 teaspoon salt
- 1/2 teaspoon sugar
- 4 cups beef broth (low-sodium)
- 2 cups chicken broth (low-sodium)
- 1/2 cup dry white wine (optional)
- 3 sprigs fresh thyme
- 1 bay leaf
- Salt and freshly ground black pepper, to taste
- 4 slices of baguette, about 1-inch thick
- 1 1/2 cups grated Gruyère cheese
Instructions
- Caramelize the Onions: In a large, heavy-bottomed pot, melt the butter and olive oil over medium heat. Add the onions and salt, stirring to coat. Cook for 30 minutes, stirring occasionally, until the onions turn golden brown. Add the sugar to enhance caramelization, cooking for another 10-15 minutes until the onions are a deep caramel color.
- Deglaze the Pot: Pour in the wine (if using), scraping up any browned bits from the bottom of the pot. Let the wine cook off for 2-3 minutes.
- Simmer the Soup: Add the beef broth, chicken broth, thyme, and bay leaf. Bring to a simmer, cover, and let cook for 20-25 minutes. Discard the thyme and bay leaf, then season with salt and pepper to taste.
- Prepare the Bread Topping: While the soup simmers, preheat the oven broiler. Place the baguette slices on a baking sheet and toast under the broiler until golden, about 1-2 minutes per side.
- Assemble and Broil: Ladle the soup into oven-safe bowls, placing a slice of toasted baguette on top of each. Sprinkle generously with Gruyère cheese. Place the bowls on a baking sheet and broil until the cheese is melted and bubbly, about 2-4 minutes.
- Serve and Enjoy: Carefully remove the bowls from the oven, and serve the soup hot.
- Prep Time: 15 minutes
- Cook Time: 1 hour 15 minutes
- Category: soup
