Ingredients:

  • 6 large yellow onions, thinly sliced
  • 4 tbsp unsalted butter
  • 1 tbsp olive oil
  • 1 tsp granulated sugar
  • 1 tsp salt
  • ½ tsp black pepper
  • 8 cups beef stock
  • ½ cup dry white wine
  • 2 cloves garlic, minced
  • 1 bay leaf
  • 1 sprig fresh thyme
  • 1 French baguette, sliced into 1-inch rounds
  • 2 cups shredded Gruyère cheese
  • ½ cup grated Parmesan cheese

Instructions:

  1. Melt butter and oil over medium heat in a large Dutch oven. Add sliced onions and stir until translucent.
  2. Sprinkle in sugar and salt, then reduce heat to medium-low.
  3. Cook, stirring occasionally, until onions are a deep, mahogany brown and have a jam-like consistency.
  4. Add minced garlic and cook for 1 minute.
  5. Pour in the white wine to deglaze, scraping the bottom of the pot to release the browned bits.
  6. Stir in the beef stock, bay leaf, and thyme.
  7. Simmer uncovered for 30 minutes to allow the flavors to meld.
  8. Preheat the broiler.
  9. Ladle the soup into oven-safe crocks.
  10. Place a toasted baguette slice on top of each bowl, then top with Gruyère and Parmesan cheese.
  11. Broil for 2–4 minutes until the cheese is bubbling and has developed small, charred brown spots.