Gratin Onion Soup

Instructions

1. 1
   In a large pot over medium heat, melt the butter and vegetable oil.
2. 2
   Add the julienned onions and sauté for 5 minutes until they begin to soften.
3. 3
   Add the sugar (optional) and fresh thyme. Cook the onions over low heat for 40 minutes, stirring occasionally, until they are deeply caramelized and golden brown.
4. 4
   Pour in the white wine and cook for 2 minutes until the alcohol evaporates and the pot is deglazed.
5. 5
   Sprinkle the flour over the onions and cook, stirring, for 2 minutes.
6. 6
   Stir in the hot beef broth and bring to a boil. Reduce heat and simmer for 20 minutes.
7. 7
   Season with salt and black pepper to taste.
8. 8
   While the soup simmers, toast the artisanal bread slices until crispy.
9. 9
   To serve: Distribute the hot soup into individual deep bowls.
10. 10
    Place a toasted bread slice on top of the soup in each bowl.
11. 11
    Generously cover the bread with the grated Gruyère cheese.
12. 12
    Broil the bowls under the oven grill for 3-5 minutes, or use a kitchen torch, until the cheese is bubbling and golden.
13. 13
    Serve immediately so the bread absorbs the soup while the cheese remains crispy.