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French Onion Soup Recipe

Bubbling gruyere cheese and crispy baguette top a brothy base full of perfectly braised onions in this showstopping French onion soup recipe. Whether you're making it to warm up on a cold day or for a delicious date night in, this feels luxurious and cozy each and every time. 

Course Soup
Cuisine French
Prep 15 minutes
Cook 4 hours 30 minutes
Total 4 hours 45 minutes
Servings 6 servings
Calories 394 kcal
Author Michelle

Ingredients

Soup:

  • 3 tablespoons unsalted butter cut into 3 pieces
  • 6 large yellow onions about 4 pounds, halved and cut into ¼-inch thick slices
  • Table salt
  • 2 cups water plus extra for deglazing
  • ½ cup dry sherry
  • 4 cups chicken broth
  • 2 cups beef broth
  • 6 sprigs fresh thyme tied with kitchen twine
  • 1 bay leaf
  • Ground black pepper

Cheese Croutons:

  • 1 small baguette cut into ½-inch slices
  • 8 ounces shredded Gruyere cheese about 2½ cups

Directions

  1. Braise/Caramelize Onions: Adjust oven rack to lower-middle position and heat oven to 400 degrees F. Generously spray inside of heavy-bottomed large (at least 7-quart) Dutch oven with nonstick cooking spray. Place butter in the pot and add onions and 1 teaspoon salt. Cook, covered, 1 hour (onions will be moist and slightly reduced in volume). Remove pot from oven and stir onions, scraping bottom and sides of pot. Return pot to oven with lid slightly ajar and continue to cook until onions are very soft and golden brown, 1½ to 1¾ hours longer, stirring onions and scraping bottom and sides of pot after 1 hour.

  2. Carefully remove pot from oven and place over medium-high heat. Using oven mitts to handle pot, cook onions, stirring frequently and scraping bottom and sides of pot, until liquid evaporates and onions brown, 15 to 20 minutes, reducing heat to medium if onions are browning too quickly. Continue to cook, stirring frequently, until pot bottom is coated with dark crust, 6 to 8 minutes, adjusting heat if necessary. (Scrape any crust that collected on spoon back into onions.) Stir in ¼ cup water, scraping pot bottom to loosen crust, and cook until water evaporates and pot bottom has formed another dark crust, 6 to 8 minutes. Repeat process of deglazing 2 or 3 more times, until onions are very dark brown. Stir in sherry and cook, stirring frequently, until sherry evaporates, about 5 minutes.

  3. Finish the Soup: Stir in broths, 2 cups water, thyme, bay leaf, and ½ teaspoon salt, scraping up any final bits of browned crust on bottom and sides of pot. Increase heat to high and bring to simmer. Reduce heat to low, cover, and simmer 30 minutes. Remove and discard herbs, then season with salt and pepper.

  4. Broil with Cheesy Baguette Slices: While soup simmers, arrange baguette slices in single layer on baking sheet and bake in 400-degree oven until bread is dry, crisp, and golden at edges, about 10 minutes. Set aside.

  5. Adjust oven rack 6 inches from broiler element and heat broiler. Set individual broiler-safe crocks on baking sheet and fill each with about 1¾ cups soup. Top each bowl with 1 or 2 baguette slices (do not overlap slices) and sprinkle evenly with Gruyere. Broil until cheese is melted and bubbly around edges, 3 to 5 minutes. Let cool 5 minutes before serving.

Recipe Notes

  • Equipment: 7-quart Dutch oven / Broiler-safe soup crocks
  • Onions: Use yellow onions for the best balance of flavor.
  • Broth: This recipe calls for a combination of beef and chicken broth; you can adjust the ratios based on what you have on hand and substitute stock if you'd like.
  • Baguette: Sliced French baguette is the traditional topping for French onion soup, but any crusty bread will suffice, and if you're in a pinch, you can use big croutons, too!
  • Cheese: Gruyere is the standard, but shredded Swiss makes a great substitute.
  • Broiling: If using ordinary soup bowls, sprinkle the toasted bread slices with Gruyère and return them to the broiler until the cheese melts, then float them on top of the soup. 
  • Make-Ahead: For the best flavor, make the soup a day or 2 in advance. Alternatively, the onions can be prepared through step 1, cooled in the pot, and refrigerated for up to 3 days before proceeding with the recipe.
  • Storage: Leftover soup can be refrigerated for up to 4 days.
  • Freezing: The soup can be frozen in an airtight container for up to 3 months. Do not freeze the cheese-covered bread with the soup; freeze the soup separately and add the bread and cheese before serving.
  • Recipe adapted from Cook's Illustrated
Nutrition Facts
French Onion Soup Recipe
Amount Per Serving
Calories 394 Calories from Fat 171
% Daily Value*
Fat 19g29%
Saturated Fat 11g69%
Cholesterol 56mg19%
Sodium 602mg26%
Potassium 425mg12%
Carbohydrates 32g11%
Fiber 3g13%
Sugar 5g6%
Protein 17g34%
Vitamin A 580IU12%
Vitamin C 20.7mg25%
Calcium 464mg46%
Iron 2.2mg12%
* Percent Daily Values are based on a 2000 calorie diet.