Classic French Onion Soup with Gruyère Croutons

Ingredients

• 4 tablespoons unsalted butter
• 2 pounds yellow onions, thinly sliced
• 1 teaspoon sugar
• 1 teaspoon salt
• 1 teaspoon black pepper
• 1 cup dry white wine
• 6 cups beef broth
• 2 tablespoons all-purpose flour
• 2 teaspoons fresh thyme, chopped
• 1 tablespoon balsamic vinegar

• 4 slices French baguette, toasted
• 1 cup Gruyère cheese, grated

Method

1. 01
   Melt the butter in a large pot over medium heat.
2. 02
   Add the sliced onions and cook, stirring occasionally, until they are soft and caramelized, about 25-30 minutes.
3. 03
   Sprinkle the sugar, salt, and black pepper over the onions and stir well.
4. 04
   Stir in the flour and cook for another 2 minutes, stirring constantly.
5. 05
   Add the white wine to the pot, scraping up any browned bits from the bottom.
6. 06
   Pour in the beef broth and add the thyme. Bring to a simmer and cook for 20 minutes.
7. 07
   Stir in the balsamic vinegar and adjust seasoning with salt and pepper to taste.
8. 08
   Preheat the broiler. Place the toasted baguette slices on a baking sheet and sprinkle each with grated Gruyère cheese.
9. 09
   Broil until the cheese is melted and bubbly, about 2-3 minutes.
10. 10
    Ladle the soup into bowls and top each with a Gruyère crouton before serving.