French onion soup

Ingredients:

• 4 large onions (about 2 pounds/900g), thinly sliced
• 3 tablespoons (45g) unsalted butter
• 1 tablespoon (15ml) olive oil
• 1 teaspoon (5g) sugar
• 1 teaspoon (5g) salt, plus more to taste
• 1/4 cup (60ml) dry white wine
• 8 cups (2 liters) beef broth, preferably homemade
• 1/4 teaspoon (1g) freshly ground black pepper
• 1/2 teaspoon (1g) dried thyme
• 1 bay leaf
• 6-8 slices of French baguette
• 2 cups (200g) grated Gruyère cheese

Instructions:

1. In a large, heavy-bottomed pot, melt the butter with the olive oil over medium heat. Add the onions, sugar, and salt.
2. Cook the onions, stirring frequently, until they are deep golden brown and caramelized, about 30-40 minutes. Adjust the heat to prevent burning.
3. Add the white wine to the caramelized onions, scraping up any browned bits from the bottom of the pot. Simmer until the wine has evaporated, about 3 minutes.
4. Stir in the beef broth, black pepper, thyme, and bay leaf. Bring to a boil, then reduce the heat and let it simmer, uncovered, for 30 minutes. Discard the bay leaf and adjust seasoning with additional salt and pepper if needed.
5. While the soup is simmering, preheat the broiler. Arrange the baguette slices on a baking sheet and toast under the broiler until golden brown on both sides. Remove and set aside.
6. Ladle the hot soup into oven-safe bowls. Place a toasted baguette slice on top of each bowl and generously sprinkle with the grated Gruyère cheese.
7. Place the bowls on a baking sheet and broil in the oven until the cheese is melted, bubbly, and golden brown, about 3-5 minutes.
8. Carefully remove the bowls from the oven and let cool for a few minutes before serving.

Notes:

For a richer flavor, you can use a combination of beef and chicken broth. The soup can be made ahead and stored in the refrigerator for up to 3 days. Reheat gently before serving. For a vegetarian version, substitute vegetable broth for beef broth. Serve with additional toasted baguette slices on the side.