# Components:
→ Onions
01 - 5 large yellow onions, thinly sliced
→ Aromatics
02 - 3 tablespoons unsalted butter
03 - 2 tablespoons olive oil
04 - 2 garlic cloves, minced
05 - 1 teaspoon sugar
→ Broth & Flavorings
06 - 8 cups beef broth or vegetable broth for vegetarian option
07 - 1/2 cup dry white wine
08 - 2 teaspoons fresh thyme leaves or 1 teaspoon dried thyme
09 - 2 bay leaves
10 - 1 tablespoon Worcestershire sauce
11 - Salt and freshly ground black pepper to taste
→ Topping
12 - 1 baguette, sliced into 1/2-inch thick rounds
13 - 2 cups Gruyère cheese, grated
14 - 1/2 cup Parmesan cheese, grated (optional)
# Directions:
01 - In a large Dutch oven over medium heat, melt the butter with olive oil. Add the sliced onions and sugar. Cook, stirring frequently, until onions are very soft and deeply caramelized, approximately 40 to 45 minutes.
02 - Add the minced garlic and cook for 1 minute until fragrant and fully incorporated into the caramelized onions.
03 - Pour in the dry white wine, scraping up any browned bits from the bottom of the Dutch oven. Simmer for 2 to 3 minutes until the wine is slightly reduced.
04 - Add the broth, thyme, bay leaves, and Worcestershire sauce. Bring to a simmer, reduce heat to low, and cook uncovered for 20 to 30 minutes. Season with salt and pepper to taste. Remove and discard bay leaves.
05 - While the soup simmers, preheat your oven broiler. Arrange baguette slices on a baking sheet and toast under the broiler until golden brown, approximately 1 to 2 minutes per side.
06 - Ladle the hot soup into oven-safe bowls. Top each bowl with a toasted baguette slice and a generous handful of grated Gruyère cheese, and Parmesan cheese if desired.
07 - Place filled bowls on a baking sheet and broil under the preheated broiler until the cheese is melted and bubbling, approximately 2 to 4 minutes.
08 - Remove from broiler and serve immediately, garnished with fresh thyme leaves if desired.