Soupe à l’Oignon (French Onion Soup)
French onion soup builds deep sweetness from slow-cooked onions, beef stock, toasted baguette, and a bubbling Gruyère topping.
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1 hr 10 mintotal
Prep 15 min · Cook 55 min
- Serves
- 2
- Difficulty
- Medium
- Spice
- None
Ingredients
Quantities are for 2 servings.
You'll need: Stovetop, Oven.
No inactive time is needed, but the onions need patient low heat; rushing this step leaves the soup pale and sharp.
Method
Melt the measured butter with the measured olive oil in a heavy pan over medium-low heat. Add the onions and cook slowly, stirring often, until they become deep golden and sweet.
Add the garlic and cook briefly. Sprinkle in the measured flour and stir until it coats the onions without forming dry lumps.
Pour in the warm beef stock gradually while stirring. Add the bay leaf, thyme, salt, and black pepper, then simmer until the soup is savory and lightly thickened.
Remove the bay leaf. Ladle the soup into oven-safe bowls, place the toasted baguette slices on top, and cover with the grated Gruyère cheese.
Bake or broil at 220°C until the cheese melts, bubbles, and turns lightly golden. Serve carefully while hot.
How to tell it's done
The soup should be clear but full-bodied, with silky onions and a bubbling golden cheese cap.
Getting it right
Tip
Do not rush the onions; their deep color and sweetness are the main flavor base of the soup.
What to serve it with
Serve as a warm starter or a light dinner with a simple green salad.
Common mistakes
- The soup tastes thin or harsh.
- Cook the onions until deeply golden before adding stock, then simmer long enough for the broth to taste rounded.
Substitutions
- Vegetable stock may be used for a lighter version, but it changes the classic beef-stock profile.
- Cheddar Cheese can replace Gruyère Cheese when Gruyère is unavailable, but the flavor will be sharper and less traditional.
- Use gluten-free bread and a suitable thickener only after checking labels if avoiding gluten.
Storing and reheating
Refrigerate the onion soup without bread and cheese for up to 4 days. Reheat the soup, then add fresh toast and Gruyère before broiling; freeze the soup base for up to 2 months.
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