French Onion Soup with Gruyère Croutons

Ingredients

• 4 medium yellow onions, thinly sliced
• 2 tablespoons unsalted butter
• 2 tablespoons olive oil
• 4 cups beef broth, low sodium
• 1 cup chicken broth, low sodium
• 1 cup dry white wine
• 1 teaspoon sugar
• 1 teaspoon salt, to taste
• 1 teaspoon black pepper, freshly ground
• 1 tablespoon all-purpose flour, optional, for thickening
• 2 teaspoons fresh thyme, chopped
• 1 tablespoon balsamic vinegar

• 1 baguette French bread, sliced
• 1 cup Gruyère cheese, grated
• 2 tablespoons olive oil

Method

1. 01
   In a large pot, heat olive oil and butter over medium heat. Add the sliced onions and cook, stirring occasionally, until they are caramelized and golden brown, about 25-30 minutes.
2. 02
   Sprinkle sugar over the onions to enhance their sweetness, then add flour to thicken the soup slightly, if desired. Stir well to combine.
3. 03
   Pour in the dry white wine, scraping up any browned bits from the bottom of the pot. Allow the wine to reduce by half.
4. 04
   Add the beef broth, chicken broth, thyme, salt, and pepper to the pot. Bring the mixture to a simmer and let it cook for 30 minutes to develop the flavors.
5. 05
   While the soup simmers, preheat the oven to 400°F (200°C). Arrange the baguette slices on a baking sheet, brush with olive oil, and top with grated Gruyère cheese.
6. 06
   Bake the croutons in the oven for 10 minutes, or until the cheese is melted and bubbly.
7. 07
   Stir in the balsamic vinegar into the soup and adjust seasoning with additional salt and pepper if needed.
8. 08
   Ladle the soup into bowls and top with Gruyère croutons just before serving.