Go Back

French Onion Soup

This classic French Onion Soup is built around slow, mindful caramelization of yellow onions, which develop a deep sweetness and rich flavor. The soup is simmered with beef broth and white wine, then topped with toasted baguette slices and melted Gruyère cheese, resulting in a comforting dish with tender onions, a flavorful broth, and a bubbly, golden cheese crust.
Print Recipe Pin Recipe
Prep Time 15 minutes
Cook Time 1 hour 10 minutes
Total Time 1 hour 25 minutes
Servings: 4
Course: Main Course
Cuisine: French
Calories: 350
Ingredients Equipment Method Notes

Ingredients
  

  • 6-8 large yellow onions thinly sliced, about 3 mm
  • 2 tablespoons butter for caramelizing onions
  • 1 tablespoon olive oil
  • 0.5 cup dry white wine for deglazing
  • 1.5 liters beef broth or good-quality store-bought
  • 2 sprigs fresh thyme crushed during cooking
  • 4 slices baguette toasted until golden
  • 1.5 cups Gruyère cheese grated
  • to taste salt and freshly ground black pepper

Equipment

  • Large heavy-bottomed pot or Dutch oven
  • Sharp chef's knife
  • Wooden spoon
  • Oven-safe bowls or crocks
  • Baking Sheet

Method
 

  1. Start by slicing your yellow onions thinly and evenly, about 3 mm slices. This helps them caramelize uniformly and develop that rich sweetness.
  2. Heat the butter and olive oil together in a large heavy-bottomed pot over medium-low heat. Once melted, add the sliced onions and stir to coat them with the fat. Cook gently, stirring every 10 minutes, allowing the onions to soften and slowly turn a golden hue.
  3. Continue cooking and stirring for about 45-60 minutes, until the onions deepen to a deep amber color and smell sweet and caramelized. This slow process is key to developing that soulful flavor.
  4. Pour in the white wine to deglaze the pan, scraping up any browned bits from the bottom. Let the wine cook off until nearly evaporated, which will intensify the flavor.
  5. Add the beef broth and throw in the thyme sprigs. Bring the mixture to a gentle simmer, then reduce the heat to low. Let it simmer uncovered for about 20 minutes, stirring occasionally to meld all the flavors.
  6. Season the soup with salt and pepper to taste. Remove the thyme sprigs and give it a final taste adjustment. Ladle the hot soup into ovenproof bowls or crocks, filling them about three-quarters full.
  7. Place the toasted baguette slices on top of each bowl, then generously sprinkle with grated Gruyère cheese. Carefully transfer the bowls onto a baking sheet for stability.
  8. Broil the bowls in the oven until the cheese bubbles and turns a lovely golden brown, about 3-5 minutes. Keep a close eye to prevent burning.
  9. Remove the bowls carefully from the oven and let them sit for a minute to cool slightly. The cheese should be gooey and bubbly, with a crispy edge on the bread.
  10. Garnish with an extra sprig of thyme if desired, then serve hot and enjoy the rich, caramelized flavors and comforting texture of this timeless dish.

Notes

For best results, take your time caramelizing the onions on low heat. The slow process is what creates the depth of flavor in this soup. Make ahead: the soup can be prepared a day in advance, and reheated gently for serving. Toast the baguette slices fresh before broiling for a perfect crunch.