No.37 The 100 Most Popular Recipes Ever · October 2026

French onion soup

Made famous by Thomas Keller

Photo: Daderot, CC0, via Wikimedia Commons

From Bouchon, 2004.

The bistro soup with the cheese lid is one of the most ordered soups in the world. Keller's onions, cooked for hours until mahogany, are the lesson.

Written in our own words and tested in a home kitchen. Get the original in Bouchon.

Ingredients

• 8 lb (3.6 kg) yellow onions (about 8 large), halved and sliced 1/4 inch thick
• 4 tbsp (56 g) unsalted butter
• Fine salt
• 2 tbsp all-purpose flour
• 1/2 cup (120 ml) dry sherry or dry white wine
• 3 quarts (2.8 L) beef stock (homemade is best)
• A bundle of thyme sprigs, parsley and a bay leaf
• 1 tbsp sherry vinegar, and black pepper
• Six 1-inch slices baguette, toasted until dry
• 3 cups (12 oz, 340 g) grated Comté or Gruyère

Steps

1. Melt the butter in a large heavy pot over medium heat. Add the onions and 1 teaspoon salt. Cover and cook 20 minutes, stirring now and then, until they have released their liquid and are soft.
2. Uncover, lower the heat to medium-low and cook, stirring every 10 to 15 minutes and scraping the bottom, until the onions are a deep, even caramel brown and reduced to about 3 cups. This takes 3 to 4 hours. If they catch, add a few tablespoons of water and scrape.
3. Sprinkle in the flour and stir 2 minutes. Add the sherry and scrape the pot clean.
4. Add the stock and herbs. Simmer 1 hour, skimming. Remove the herbs, stir in the vinegar, and season with salt and pepper.
5. Heat the broiler. Set ovenproof bowls on a sheet pan and fill them with hot soup almost to the top.
6. Float a slice of toast on each, cover thickly with cheese so it reaches the rim of the bowl, and broil until the cheese is bubbling and browned in spots, 3 to 5 minutes. Serve carefully; the bowls are very hot.

Chef's tips

• The onions can be cooked days ahead and refrigerated; they also freeze.
• Low and slow matters: high heat browns onions unevenly and makes them bitter.

This is Chef Amazing's write-up of the dish, tested for a home kitchen. The original is in Bouchon by Thomas Keller: get the book, No. 53 on The 100 Greatest Cookbooks.

← No. 36Coq au vin→ No. 38Ratatouille