Ingredients

4 large yellow onions, thinly sliced
4 tbsp unsalted butter
1 tbsp olive oil
8 cups beef broth
1 cup dry white wine
2 sprigs fresh thyme
2 bay leaves
Salt and pepper to taste
1 French baguette, sliced
2 cups grated Gruyère cheese

Directions

In a large pot, melt the butter with the olive oil over medium heat. Add the sliced onions and cook, stirring frequently, until they are deep golden brown and caramelized, about 40 minutes.

Add the white wine to the pot, scraping up any browned bits from the bottom. Then add the beef broth, thyme, and bay leaves. Bring to a boil, then reduce heat and simmer for 20 minutes. Season with salt and pepper to taste.

While the soup is simmering, preheat your oven to 400°F (200°C). Arrange the baguette slices on a baking sheet and toast them in the oven until golden brown, about 5-7 minutes.

Remove the thyme sprigs and bay leaves from the soup. Ladle the soup into oven-safe bowls. Top each bowl with a slice of toasted baguette and a generous amount of grated Gruyère cheese.

the bowls on a baking sheet and broil in the oven until the cheese is bubbly and golden brown, about 3-5 minutes. Serve immediately.