Equipment
Ingredients
Soup Base
- 1000 g yellow onions, halved and thinly sliced
- 50 g unsalted butter
- 15 ml olive oil
- 5 g kosher salt
- 3 g white sugar
- 2 garlic, minced
- 15 g all-purpose flour
- 120 ml dry white wine
- 1000 ml beef stock, high quality or homemade
- 3 g fresh thyme, tied in a bundle
- 1 bay leaf
Gratin Topping
- 100 g baguette, sliced 2cm thick
- 1 garlic, halved
- 150 g gruyère cheese, freshly grated
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 501 kcal
- Protein
- 20 g
- Carbohydrates
- 41 g
- Fat
- 27 g
- Fiber
- 6 g
- Sugar
- 12 g
- Sodium
- 1790 mg
- Saturated Fat
- 14 g
- Monounsaturated Fat
- 10 g
- Polyunsaturated Fat
- 2 g
- Cholesterol
- 68 mg
- Potassium
- 615 mg
- Calcium
- 476 mg
- Iron
- 1.5 mg
- Magnesium
- 62 mg
- Phosphorus
- 389 mg
- Zinc
- 2.3 mg
- Vitamin A
- 189 mcg
- Vitamin C
- 21 mg
- Vitamin D
- 0.2 mcg
- Vitamin E
- 1.1 mg
- Vitamin K
- 6 mcg
- Vitamin B6
- 0.5 mg
- Vitamin B12
- 0.8 mcg
- Thiamin
- 0.29 mg
- Riboflavin
- 0.31 mg
- Niacin
- 3.4 mg
- Folate
- 82 mcg
- Water
- 520 g
- Alcohol
- 3 g
Sources: USDA FoodData Central
Method
Place the Dutch oven over medium heat. Add the unsalted butter and olive oil, heating until the butter is completely melted and slightly foaming.
Add the sliced yellow onions, kosher salt, and white sugar to the Dutch oven. Toss well with a wooden spoon to coat the onions in the fats.
Cook the onions, stirring every 5 minutes. As they reduce and begin to brown, lower the heat slightly and scrape the bottom of the pot to incorporate the fond. Continue until they reach a deep mahogany brown.
Stir the minced garlic into the caramelized onions and cook for 1 minute until fragrant.
Sprinkle the all-purpose flour over the onion mixture. Stir continuously to cook out the raw flour taste.
Pour in the dry white wine to deglaze the pot. Scrape the bottom vigorously with the wooden spoon to release any remaining browned bits.
Pour in the beef stock, then add the fresh thyme bundle and bay leaf. Bring to a boil, then reduce heat and gently simmer partially covered.
While the soup simmers, preheat the oven to 200°C/400°F. Arrange baguette slices on a baking sheet and toast until dry and golden brown around the edges. Remove from the oven and immediately rub one side of each slice with the halved raw garlic clove.
Remove the thyme stems and bay leaf from the broth. Ladle the hot soup into oven-safe soup crocks, leaving about 2cm of space at the top. Float 1 or 2 toasted baguette slices in each crock, and cover generously with grated Gruyère cheese.
Preheat the broiler. Place the crocks on a sturdy baking sheet and carefully transfer them to the oven. Broil until the cheese is melted, aggressively bubbling, and charred in spots. Serve immediately.
Chef's Notes
- Patience is the only secret to incredible French Onion Soup. Caramelizing onions properly takes 45-60 minutes. There is no shortcut, and attempting to speed it up with high heat will yield fried onions instead of jammy, sweet ones.
- Using a mix of yellow and red onions can add a wonderful complexity to the soup, but standard yellow onions offer the most classic flavor profile.
- If your beef stock is unsalted, make sure to taste the final broth before ladling it into the crocks. The cheese adds salt, but the broth needs to stand on its own.
- Rubbing the freshly toasted croutons with raw garlic adds a profound, sharp aromatic punch that cuts through the richness of the cheese and sweet onions.
Storage
Refrigerator: 4 days — Store the soup base separately from the baguette and cheese.
Freezer: 3 months — Freeze only the soup base. Thaw overnight before reheating.
Reheating: Reheat soup base on the stovetop until simmering. Ladle into crocks, add fresh toast and cheese, and broil.
Troubleshooting
Onions are browning too fast and burning before breaking down
Cause: Heat is too high or pot is too thin, causing rapid water evaporation
Fix: Add 1-2 tablespoons of water to immediately lower the pan temperature and scrape up the burnt fond
Prevention: Keep heat at medium or medium-low and use a heavy-bottomed Dutch oven
Broth tastes flat or overly sweet
Cause: Onions were not caramelized deeply enough, or stock lacked savory depth
Fix: Stir in a splash of dry sherry, sherry vinegar, or a few drops of Worcestershire sauce to balance the sweetness
Prevention: Ensure onions reach a dark mahogany color before proceeding, and use high-quality bone broth
Bread sinks immediately into the soup
Cause: Bread was not toasted enough or sliced too thinly
Fix: Cannot be fixed once submerged, but will still taste delicious as a savory porridge
Prevention: Slice bread at least 2cm thick and toast until completely dried out
Cultural Context
Soupe à l'oignon gratinoise has origins tracing back to ancient Roman times, but the modern version was perfected in 18th century Paris. It became the signature dish of Les Halles, the historic wholesale market, where it was served to laborers and late-night revelers alike as a restorative, cheap, and deeply warming meal.
