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Classic French Onion Soup

Deeply caramelized onions in a rich beef broth, topped with toasted baguette and bubbly Gruyère. A timeless French bistro classic.
Print Recipe
Prep Time 15 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 30 minutes
Servings: 4 bowls
Course: Soup
Cuisine: French
Ingredients Equipment Method Notes

Ingredients
  

  • ​ ​ ​ ​
  • 6 ​ large yellow onions about 2.5 lbs
  • 4 tbsp unsalted butter ​
  • 6 cups beef broth ​
  • 1/2 cup dry white wine ​
  • 3 ​ sprigs fresh thyme or 1 tsp dried
  • 1 ​ bay leaf ​
  • 4 to 6 ​ thick slices French baguette toasted
  • 1.5 cups Gruyère cheese grated (150g)
  • ​ ​ Salt and freshly ground black pepper to taste
  • 1 tsp Worcestershire sauce optional

Equipment

  • Large heavy-bottomed pot or Dutch oven ​

Method
 

  1. ​
  2. Caramelize the onions: Slice onions thinly. Melt butter in a heavy pot over medium-low heat. Add onions and salt. Cook slowly, stirring occasionally, for 40 to 50 minutes until deep golden brown.
  3. Deglaze and build the broth: Pour in white wine and scrape up browned bits. Simmer 2 to 3 minutes. Add beef broth, thyme, and bay leaf. Simmer 20 to 25 minutes. Season with salt and pepper.
  4. Toast the bread and assemble: Preheat broiler. Toast baguette slices. Remove thyme and bay leaf. Ladle soup into oven-safe bowls. Top with toasted bread and grated Gruyère.
  5. Broil and serve: Broil 2 to 4 minutes until cheese is melted and bubbly. Let cool 2 to 3 minutes before serving.

Notes

Do not rush the onions. Low heat and patience prevent bitterness and build deep flavor.
Always grate your own cheese. Pre-shredded cheese will not melt smoothly.
The soup base can be made 2 to 3 days ahead. Add bread and cheese just before serving.