Go Back

French Onion Soup

This classic French onion soup is made by slowly caramelizing thinly sliced onions until they develop a deep, glossy amber color, releasing their natural sweetness. The caramelized onions are simmered with rich beef broth, white wine, and herbs, then topped with toasted baguette slices and melted Gruyère cheese. The final dish boasts a velvety, flavorful broth with tender onions and a bubbly, golden cheese crust on top.
Print Recipe Pin Recipe
Prep Time 15 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 30 minutes
Servings: 4
Course: Main Course
Cuisine: French
Calories: 350
Ingredients Equipment Method Notes

Ingredients
  

  • 4 large yellow onions thinly sliced
  • 2 tablespoons unsalted butter for caramelizing
  • 0.5 cup dry white wine for deglazing
  • 4 cups beef broth rich and savory
  • 4 slices baguette toasted until golden
  • 1.5 cups Gruyère cheese grated
  • 1 sprig fresh thyme optional

Equipment

  • Large heavy-bottomed pot
  • Wooden spoon
  • Oven-safe bowls
  • Baking sheet
  • Mandoline or sharp knife

Method
 

  1. Slice the onions thinly using a sharp knife or mandoline, aiming for about 2-3 mm thickness. Set aside.
  2. Heat the large heavy-bottomed pot over medium-low heat and add the butter. Let it melt gently, releasing a nutty aroma, and then add the sliced onions.
  3. Stir the onions frequently to coat them evenly in butter. Cook slowly over low heat, stirring often, for about 45-60 minutes until they turn a deep, glossy amber color and smell sweet and caramelized.
  4. Pour in the white wine to deglaze the pan, scraping up any browned bits from the bottom. Let the wine reduce for 3-5 minutes until mostly evaporated and the mixture is fragrant.
  5. Add the beef broth and a sprig of thyme if using. Bring the soup to a gentle simmer and cook for an additional 20 minutes, tasting and adjusting salt as needed.
  6. While the soup simmers, pre-toast the baguette slices in the oven at 180°C (350°F) until golden and crisp, about 5 minutes.
  7. Remove the thyme from the soup. Ladle the hot broth into oven-safe bowls, then top each with a toasted baguette slice.
  8. Sprinkle generously with grated Gruyère cheese, covering the bread completely. Place the bowls on a baking sheet.
  9. Bake in the oven at 200°C (390°F) for 10-15 minutes until the cheese is melted, bubbly, and golden. For a more browned topping, briefly broil for 1-2 minutes, watching carefully.
  10. Remove from the oven and let sit for 2 minutes. Serve hot, garnished with additional thyme if desired, and enjoy the rich, comforting flavors.

Notes

Slow caramelization is key for depth of flavor. Use low heat and patience. To intensify the sweetness, cook the onions longer until deeply amber. Adjust seasoning to taste after simmering.