Ingredients:

  • 4 large yellow onions, thinly sliced
  • 4 tablespoons unsalted butter
  • 1 tablespoon olive oil
  • 1 teaspoon sugar (optional)
  • 4 cups beef broth (or vegetable broth for vegetarian)
  • 1 cup dry white wine (optional)
  • 2 teaspoons fresh thyme leaves or 1 teaspoon dried thyme
  • 1 bay leaf
  • Salt, to taste
  • Freshly ground black pepper, to taste
  • 4 slices of French baguette, toasted
  • 1 ½ cups grated Gruyère cheese

Instructions:

  1. Heat the butter and olive oil in a large pot over medium heat. Add the sliced onions and sugar; cook, stirring occasionally, until onions are soft and golden brown (about 30 minutes).
  2. Pour in the wine and scrape any browned bits from the bottom of the pot. Stir in the broth, thyme, bay leaf, and season with salt and pepper.
  3. Bring to a simmer; reduce heat and cook uncovered for 15 minutes. Taste and adjust seasoning if needed.
  4. Preheat the broiler. Place toasted baguette slices on top of the soup in each bowl. Generously sprinkle with cheese.
  5. Transfer bowls to the broiler; cook for 3-5 minutes, or until the cheese is melted and bubbly.
  6. Carefully remove from the oven, garnish with additional thyme if desired, and serve hot.