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A close-up shot of French Onion Soup in a white bowl, highlighting the rich, dark broth and caramelized onions.

French Onion Soup: The Ultimate Classic Recipe

Discover the secrets to a perfect French Onion Soup with this classic recipe. Learn how to achieve deeply caramelized onions, a rich and savory beef broth, and a perfectly melted Gruyère cheese crust for the ultimate comfort food experience.
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Prep Time 20 minutes
Cook Time 1 hour 30 minutes
Total Time 1 hour 50 minutes
Servings: 6 servings
Course: Appetizer, Dinner, Soup
Cuisine: French
Calories: 450
Ingredients Equipment Method Notes

Ingredients
  

  • 3 tbsp Unsalted Butter
  • 1 tbsp Olive Oil
  • 6 Large Yellow Onions thinly sliced
  • 2 cloves Garlic minced
  • 1 tsp Sugar helps with caramelization
  • 1 tsp Salt or to taste
  • 1/2 tsp Black Pepper freshly ground
  • 1/2 cup Dry White Wine or Brandy such as Sauvignon Blanc or Cognac
  • 8 cups Beef Broth high-quality
  • 1 tsp Fresh Thyme Leaves
  • 1 Baguette sliced into 1-inch thick rounds
  • 2 cups Gruyère Cheese shredded
  • 1/4 cup Parmesan Cheese shredded, optional

Equipment

  • 1 Dutch Oven or Heavy-Bottomed Pot
  • 6 Oven-Safe Soup Bowls
  • 1 Baking Sheet

Method
 

  1. In a large Dutch oven or heavy-bottomed pot, melt butter and olive oil over medium heat. Add the sliced onions, sugar, salt, and pepper. Cook, stirring occasionally, until the onions are soft and translucent, about 15-20 minutes.
  2. Reduce heat to medium-low and continue to cook, stirring every 5-10 minutes, until the onions are deeply browned and caramelized. This will take 45-60 minutes. Be patient, as this step develops the core flavor.
  3. Add the minced garlic and cook for 1 minute until fragrant. Pour in the wine or brandy to deglaze, scraping any browned bits from the bottom of the pot. Cook until the liquid has mostly evaporated.
  4. Stir in the beef broth and fresh thyme. Bring to a simmer, then reduce heat to low, cover, and let it gently simmer for at least 30 minutes to let the flavors meld.
  5. While the soup simmers, preheat your oven to 400°F (200°C). Arrange baguette slices on a baking sheet and toast for 8-10 minutes, or until golden and crisp. Set aside.
  6. Preheat the broiler. Ladle the hot soup into oven-safe bowls. Place one or two toasted baguette slices on top of the soup in each bowl. Generously top with shredded Gruyère and Parmesan cheese.
  7. Carefully place the bowls on a baking sheet and put under the broiler for 2-4 minutes, or until the cheese is bubbly, melted, and golden brown. Watch closely to prevent burning. Serve immediately.

Notes

For the best flavor, use a combination of Gruyère and a sharp cheese like Parmesan or Asiago.
The soup can be made up to 3 days in advance and stored in the refrigerator. Reheat gently on the stove before topping with bread and cheese and broiling.
Ensure your bowls are rated as 'oven-safe' or 'broiler-safe' before putting them under the broiler.