Ingredients:

• 4 large onions, thinly sliced
• 4 tablespoons butter
• 4 cups beef broth
• 2 cups chicken broth
• 1/2 cup dry white wine (optional)
• 1 teaspoon sugar
• 1 teaspoon Worcestershire sauce
• Salt and black pepper to taste
• Baguette slices
• Gruyere or Swiss cheese, grated

Instructions:

1. In a large pot, melt the butter over medium heat. Add the sliced onions and cook until they become caramelized and golden brown, stirring occasionally. This process may take around 30-40 minutes.
2. Once the onions are caramelized, add the sugar and continue cooking for another 5 minutes to enhance the flavor.
3. Pour in the beef broth and chicken broth, followed by the white wine if using. Add Worcestershire sauce, salt, and black pepper. Bring the mixture to a simmer and let it cook for about 20-30 minutes to allow the flavors to meld together.
4. While the soup simmers, preheat the broiler in your oven. Place the baguette slices on a baking sheet and toast them until they become golden and crispy.
5. Ladle the hot soup into oven-safe bowls or crocks. Top each bowl with a couple of toasted baguette slices, and sprinkle a generous amount of grated Gruyere or Swiss cheese on top.
6. Place the bowls on a baking sheet and put them under the broiler until the cheese melts and turns golden and bubbly.
7. Carefully remove the soup bowls from the oven (they will be hot), and let them cool slightly before serving.

Enjoy your homemade French Onion Soup with its rich, caramelized onion flavor and cheesy goodness!