Classic French Onion Soup
Deeply caramelized onion soup topped with toasted baguette and a blanket of molten Gruyère.
About This Recipe
French onion soup is an exercise in patience and the Maillard reaction. The transformation of raw onions into a deep, sweet, mahogany-coloured mass over 45–60 minutes is the entire secret of this dish. Rushed onions taste like onion soup. Properly caramelized onions taste like a revelation.
Ingredients
Serves 4
- 1.5 kgyellow onions(halved and thinly sliced)
- 60 gunsalted butter
- 2 tbspolive oil
- 1 tspgranulated sugar
- 3 clovesgarlic(minced)
- 200 mldry white wine or dry sherry
- 1 litregood beef or vegetable stock
- 2 sprigsfresh thyme
- 1bay leaf
- 1 tbspWorcestershire sauce
- 1baguette(cut into 2cm rounds)
- 200 gGruyère(grated (or Comté, Emmental))
Instructions
- 1
The long caramelization
Melt butter with olive oil in a large, heavy-bottomed pot over medium heat. Add all onions and salt. Toss to coat. Cook uncovered, stirring every 10 minutes, for 45–60 minutes until deeply golden-brown and jammy. Add sugar halfway through to help caramelization.
Do not rush. If onions start catching (sticking), add a splash of water and scrape up the brown bits — those bits are flavour.
- 2
Add garlic and wine
Add garlic, cook 1 minute. Pour in wine. Scrape up all the brown bits from the bottom of the pot. Simmer until wine is mostly evaporated, about 5 minutes.
- 3
Build the soup
Add stock, thyme, bay leaf and Worcestershire sauce. Simmer 15–20 minutes. Remove thyme and bay leaf. Taste — season assertively with salt and pepper.
- 4
Prepare the croutons
Arrange baguette slices on a baking sheet. Bake at 200°C / 400°F for 10 minutes until very dry and toasted on both sides.
- 5
Gratinéer
Ladle soup into oven-safe bowls. Float 2 baguette croutons on top. Pile grated Gruyère generously (don't be shy — overlap with the bowl rim). Grill (broil) under a preheated grill for 3–5 minutes until cheese is bubbling, melted and spotted with golden-brown patches.
Pro Tips
- →
Patience with the onions is everything. 45 minutes minimum.
- →
Dark browned bits on the pan bottom are flavour — deglaze thoroughly.
- →
Gruyère is traditional and optimal. Comté or Emmental work well. Cheddar is a distant third.
Variations
- •
Alsatian version: use Riesling instead of beef stock for a wine-forward soup.
- •
Rich version: finish with a splash of cognac before adding stock.
Storage
Soup (without croutons or cheese) keeps 5 days refrigerated, 3 months frozen. Gratinée fresh each time.
History & Origin
French onion soup has roots in ancient Rome, but the modern version is associated with 17th–18th century Paris, where it was sold at Les Halles market as sustenance for workers and late-night revellers. King Louis XV supposedly made a version with champagne.
Frequently Asked Questions
Can I use pre-made stock?
Yes — use a good quality, low-salt stock. Homemade beef stock is sublime, but store-bought is perfectly acceptable. The caramelized onions provide most of the flavour anyway.
Can I make this vegetarian?
Yes — use vegetable stock and omit Worcestershire sauce (or use a vegan version). The soup will be slightly lighter in colour but equally delicious.
Nutrition Facts
Per serving (400g) · 4 servings total
Time Summary
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