Equipment
Ingredients
Soup Base
- 225 g unsalted butter
- 60 ml olive oil
- 1360 g yellow onion, peeled, trimmed, halved, and thinly sliced
- salt
- black pepper
- 475 ml white wine
- 475 ml heavy cream
Garnish
- 30 g chives, thinly sliced
- croutons
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 804 kcal
- Protein
- 6 g
- Carbohydrates
- 30 g
- Fat
- 70 g
- Fiber
- 4 g
- Sugar
- 13 g
- Sodium
- 722 mg
- Saturated Fat
- 39 g
- Trans Fat
- 1 g
- Monounsaturated Fat
- 23 g
- Polyunsaturated Fat
- 4 g
- Cholesterol
- 170 mg
- Potassium
- 500 mg
- Calcium
- 138 mg
- Iron
- 1.2 mg
- Magnesium
- 41 mg
- Phosphorus
- 146 mg
- Zinc
- 0.8 mg
- Vitamin A
- 615 mcg
- Vitamin C
- 20 mg
- Vitamin D
- 1.3 mcg
- Vitamin E
- 3.1 mg
- Vitamin K
- 13 mcg
- Vitamin B6
- 0.3 mg
- Vitamin B12
- 0.2 mcg
- Thiamin
- 0.18 mg
- Riboflavin
- 0.26 mg
- Niacin
- 0.8 mg
- Folate
- 57 mcg
- Water
- 325 g
- Alcohol
- 8 g
Sources: Aggregated Public Data, USDA FoodData Central
Method
Melt 225g butter with 60ml olive oil in a large, heavy-bottomed stock pot over low heat until the butter becomes frothy.
Add 1360g sliced onions, salt, and pepper to the pot. Sauté slowly over low heat, stirring frequently for 1 hour until onions are soft and tender without browning.
Increase heat to medium and pour in 475ml white wine. Simmer for approximately 30 minutes until the liquid has reduced by half.
Stir in 475ml heavy cream. Continue cooking over low heat for another 30 minutes until the total volume of the soup has reduced by one-third.
Transfer the soup to a blender or food processor in batches and purée until completely smooth.
Return the puréed soup to a clean large pot. Reheat gently over low heat, adjust seasoning with salt and pepper, and serve garnished with chives and croutons.
Chef's Notes
- The key to a sweet and flavorful onion soup is patience. Sautéing the onions over very low heat for an extended period without browning is crucial for developing their natural sugars.
- For an even smoother purée, consider passing the soup through a fine-mesh sieve after blending. This will remove any remaining fibrous bits.
- If you prefer a richer, deeper flavor, you can add a splash of brandy or sherry along with the white wine in step 3.
- Taste and adjust seasoning frequently, especially after reducing the soup, as the flavors will concentrate.
Storage
Refrigerator: 4 days — Store in an airtight container.
Freezer: 2 months — Texture may change slightly upon thawing due to cream content.
Reheating: Gently reheat in a saucepan over low heat, stirring occasionally.
Troubleshooting
Soup has a bitter or burnt flavor
Cause: Onions were cooked at too high a temperature and browned or scorched.
Fix: Cannot be fixed
Prevention: Maintain the lowest possible heat during the initial hour of cooking and stir every few minutes.
Soup is too thin or watery
Cause: Insufficient reduction of the wine or cream components.
Fix: Simmer the soup for longer before puréeing to achieve desired thickness.
Prevention: Ensure the liquid levels drop by the specified amounts (half for wine, one-third for cream) before moving to the next step.
Cultural Context
Onion soup, particularly its French iteration (Soupe à l'oignon), has a rich history dating back to Roman times. This creamy, puréed version offers a luxurious twist on the classic, emphasizing the sweetness of slow-cooked onions rather than the traditional caramelized depth achieved with broiled cheese and croutons.
