Ingredients:

  • 4 large yellow onions, thinly sliced
  • 4 tbsp unsalted butter
  • 2 tbsp olive oil
  • 1 tbsp granulated sugar
  • 4 cloves garlic, minced
  • 8 cups low-sodium beef broth
  • 1 cup dry sherry or white wine
  • 2 sprigs fresh thyme or 1 tsp dried thyme
  • Salt and pepper to taste
  • 4 slices of baguette, about 1 inch thick
  • 2 cups shredded Gruyère cheese
  • 1 cup shredded mozzarella cheese (optional)

Instructions:

  1. Heat butter and olive oil in a large pot over medium heat. Add sliced onions and a pinch of salt. Cook slowly, stirring occasionally, for 20-30 minutes or until a deep golden brown. Tip: Add sugar halfway through to enhance caramelization.
  2. Stir in minced garlic and cook for another minute. Pour in sherry or white wine, scraping the pot to release flavorful bits. Cook until liquid is reduced by half.
  3. Add beef broth and thyme. Bring to a simmer. Season with salt and pepper. Simmer for 15 minutes.
  4. Preheat the broiler. Place baguette slices on a baking sheet. Toast until golden brown.
  5. Ladle soup into oven-safe bowls. Top each bowl with toasted baguette slices, then sprinkle with Gruyère and mozzarella cheese.
  6. Place bowls under the broiler until cheese is bubbly and golden, about 2-4 minutes. Note: Watch closely to prevent burning.