Ingredients:

  • 1.36 kg yellow onions, thinly sliced
  • 57 g unsalted butter
  • 15 g olive oil
  • 2 g salt
  • 1 g black pepper
  • 2 sprigs fresh thyme
  • 120 ml non-alcoholic white wine
  • 1.4 L low-sodium beef broth
  • 1 French baguette, sliced into 1-inch rounds
  • 225 g Gruyère cheese, shredded
  • 50 g Parmesan cheese, finely grated

Instructions:

  1. Melt the butter and olive oil in a heavy-bottomed Dutch oven over medium-low heat.
  2. Stir in the sliced onions and salt. Cook, stirring occasionally, for 45 to 60 minutes until the onions shrink and turn a chestnut brown-brown color. If onions start to stick or brown too quickly, add a tablespoon of water to deglaze.
  3. Stir in the thyme and black pepper and cook for 2 minutes.
  4. Pour in the non-alcoholic white wine and increase the heat to medium. Stir constantly for 3-5 minutes until the liquid has nearly evaporated.
  5. Pour in the beef broth and bring to a gentle simmer. Lower the heat and simmer for 20 minutes.
  6. Preheat the oven to 180°C. Toast baguette slices for 5 minutes per side.
  7. Ladle the hot soup into oven-safe crocks.
  8. Place a toasted bread slice on top of each bowl, then top with shredded Gruyère and Parmesan cheese.
  9. Place crocks under the broiler for 2-4 minutes until the cheese is bubbly and golden brown.