Ingredients
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 4 large yellow onions thinly sliced
- Salt and freshly ground black pepper to taste
- 1/2 cup dry white wine
- 6 cups low-sodium beef broth
- 1 teaspoon dried thyme
- 1 bay leaf
- 1 baguette sliced and toasted
- 1 cup grated Gruyère cheese
Instructions
- In a large pot, melt butter with olive oil over medium heat. Add sliced onions with a pinch of salt, and cook, stirring occasionally, until onions are caramelized, about 40 minutes.
- Pour in white wine to deglaze the pot, scraping up any browned bits. Cook until the wine is reduced by half, about 5 minutes.
- Add beef broth, thyme, bay leaf, salt, and pepper. Bring to a simmer and cook for 20 minutes. Remove bay leaf.
- Preheat the broiler. Ladle soup into oven-safe bowls. Top each with a slice of toasted baguette and a generous amount of Gruyère cheese.
- Broil until cheese is melted and bubbly, about 3-5 minutes. Serve hot.