Go Back
French onion soup topped with a golden, bubbling Gruyère cheese crouton and thyme

French Onion Soup

Slowly caramelized onions simmered in a rich beef broth, topped with toasted baguette and bubbling Gruyère.
Print Recipe Pin Recipe
Prep Time 15 minutes
Cook Time 1 hour 30 minutes
Total Time 1 hour 45 minutes
Servings: 6 bowls
Course: dinner, Soup, Starter
Cuisine: French
Calories: 430
Ingredients Method Notes

Ingredients
  

Soup
  • 4 tablespoons unsalted butter
  • 1 tablespoon olive oil
  • 3 pounds yellow and sweet onions thinly sliced, about 5 large, 1.4 kg
  • 1 teaspoon salt
  • 1/2 teaspoon sugar
  • 3 cloves garlic minced
  • 1 teaspoon fresh thyme leaves
  • 1 tablespoon all-purpose flour
  • 1/2 cup dry white wine or dry sherry 120 ml
  • 4 cups low-sodium beef broth 1 liter
  • 2 cups low-sodium chicken broth 480 ml
  • 1 bay leaf
  • 1 teaspoon Worcestershire sauce
Topping
  • 12 slices baguette 1/2 inch thick
  • 2 cups Gruyère cheese grated, 200 g
  • 1/4 cup Parmesan cheese grated

Method
 

  1. Melt butter with oil in a Dutch oven over medium heat. Add onions, salt and sugar; cook 10 minutes, then reduce to medium-low and cook 35 to 45 minutes, stirring often, until deep golden.
  2. Stir in garlic and thyme for 1 minute, then the flour for 1 minute.
  3. Deglaze with wine, scraping up browned bits, and simmer 2 minutes.
  4. Add both broths, bay leaf and Worcestershire. Simmer uncovered 25 to 30 minutes. Season and remove the bay leaf.
  5. Toast baguette slices at 400°F (200°C) for 8 to 10 minutes until crisp.
  6. Ladle soup into oven-safe crocks, top with bread, Gruyère and Parmesan, and broil 2 to 4 minutes until bubbling and browned.

Notes

Make ahead: the soup base keeps 4 days in the fridge or 3 months in the freezer.
Vegetarian: use mushroom broth and a splash of soy sauce.
Nutrition is an estimate per bowl with topping.