French Onion Soup
Deeply caramelized onions, dark beef stock, Gruyère melted over a toasted baguette crouton. Sixty minutes mostly hands-off.
Caramelize 1 kg of sliced yellow onions in butter very slowly until mahogany (45 min), deglaze with dry white wine and a splash of cognac, simmer in good beef stock with thyme and a bay leaf, ladle into oven-safe bowls, top with toasted baguette and a thick blanket of Gruyère, broil until bubbly and bronze.
- The onions go from pale to mahogany — anything less and the soup is wan and sweet rather than savoury and deep.
- Sherry vinegar or balsamic at the end balances all that long-cooked sweetness.
- Real Gruyère AOP — not 'Swiss' from a pre-shredded bag. The melt is different.
Equipment
- Heavy-bottomed pot (Dutch oven, 5 L)
- Wide wooden spoon
- Oven-safe French onion soup bowls
- Box grater
Ингредиенты
The onions
- 1 kg yellow onions, about 5 medium, thinly sliced root-to-tip
- 60 g unsalted butter
- 15 ml neutral oil
- 5 g fine salt
- 5 g sugar, helps caramelization
The soup
- 180 ml dry white wine
- 30 ml cognac or dry sherry, optional but worth it
- 1.5 L good beef stock, homemade or low-sodium store-bought
- 4 sprigs fresh thyme
- 1 bay leaf
- 10 ml sherry vinegar, to finish
- Black pepper, to taste
Gratin top
- 1 baguette, sliced into 1.5 cm rounds and toasted dark gold
- 200 g Gruyère AOP, coarsely grated
Приготовление
- ШАГ01
Melt butter and oil in a heavy pot over medium-high heat. Tip in the onions, salt, and sugar. Stir to coat. They will look like a mountain — they will collapse.
- ШАГ02
Lower the heat to medium-low. Stir every 5 minutes or so, scraping the fond from the pan bottom. This takes 45 minutes. They will go from white → pale gold → amber → mahogany. Do not rush — high heat gives you bitter, scorched onions.
- ШАГ03
Pour in the white wine and cognac, scraping every brown bit off the pan. Simmer until the liquid is almost gone — about 3 minutes.
- ШАГ04
Pour in the beef stock. Add thyme and bay leaf. Bring to a simmer and cook 30 minutes — the soup deepens in colour and flavour.
- ШАГ05
Fish out the thyme stems and bay leaf. Stir in the sherry vinegar and a hefty grind of pepper. Taste — it should taste rounded, not just sweet. Adjust salt if needed.
- ШАГ06
Heat the broiler. Ladle soup into oven-safe bowls. Float 2 toasted baguette rounds on each. Mound Gruyère thickly over the top, covering the bread. Set the bowls on a sheet pan and broil 2–4 minutes until the cheese is bubbling and bronze with dark patches. Serve immediately, warning everyone the bowl is fire-hot.
Make ahead
The soup is BETTER the next day. Make it 24 hours ahead, refrigerate, then heat, gratin, and serve. The caramelized onion flavour rounds out overnight.
Storage
The soup base (no cheese topping) keeps 4 days in the fridge or 3 months frozen. Toast bread and gratin fresh each time — soggy croutons are inedible.
Variations
All-vegetable
Substitute mushroom stock (with a Parmesan rind simmered in) for the beef stock. Add 1 tbsp soy sauce for umami depth. The colour is paler but the flavour is honest.
Onion soup blanc
Skip the cognac and use chicken stock instead of beef. Finishes lighter, more herbal.
Extra crouton
Tear day-old country bread into chunks, toss with melted butter and Gruyère, broil until crisp, scatter over the top of the soup. Maximum crunch.
Serve with
Nutrition per serving
Nutrition values are estimates based on the metric measurements. Adjust as needed.
Частые вопросы
How dark should the onions go?
Mahogany. They should look like the rind of a Frankfurter sausage — dark, glossy brown. If they're golden, you are not done. If they are black-brown in spots, you went too far on too high a heat.
Can I use red onions?
You can, but the soup will be more pungent and lose the rounded sweetness. Yellow onions are the Lyonnais standard for a reason.
What if I don't have oven-safe bowls?
Toast the cheese-topped croutons under the broiler on a sheet pan, then float them on the soup. Less drama, same flavour.
Can I skip the cognac?
Yes — sherry vinegar at the end picks up some of that warmth. Or use dry sherry in place of both wine and cognac.
Why does mine taste flat?
Three usual culprits: (1) under-caramelized onions, (2) stock that's too thin — use a real beef stock or fortify with a Parmesan rind, (3) no acid at the end. The sherry vinegar is essential.
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