Soupe à l'Oignon
French onion soup — deeply caramelised onions in rich beef broth, topped with crusty bread and a bubbling cap of melted Gruyère. The ultimate cold-weather comfort food.
Prep Time
15 min
Cook Time
1 hour
Servings
4
Difficulty
Easy
Method
- Melt the butter with the olive oil in a large, heavy-bottomed saucepan over medium heat. Add the sliced onions and a generous pinch of salt — the salt helps draw out moisture and starts the caramelisation process. Cook slowly, stirring occasionally, for 40-45 minutes until the onions are deeply golden, sweet, and jammy. Do not rush this step.
- Add the crushed garlic and fresh thyme leaves, cook for 1 minute until fragrant. Sprinkle over the flour and stir for another minute to cook out the raw taste.
- Pour in the white wine and scrape the bottom of the pan to release all the caramelised bits. Let it bubble for 2 minutes to cook off the alcohol, then add the beef stock. Bring to a gentle simmer and cook for 15 minutes. Season with salt and pepper to taste.
- Meanwhile, toast the bread slices under a hot grill until golden on both sides. Set aside.
- Ladle the hot soup into oven-safe bowls or crocks. Place a slice of toast on top of each bowl and pile generously with grated Gruyère. Place under the grill until the cheese is bubbling, golden, and irresistibly stretchy. Serve immediately while the cheese is still molten.
Chef's Tips
- Patience with the onions: The long, slow caramelisation is what gives this soup its deep, sweet flavour. Don't turn up the heat to speed things up — you'll burn rather than caramelise.
- Use good stock: The stock is the backbone of this soup. Homemade is best, but a good-quality shop-bought stock works well too.
- Gruyère is essential: Don't substitute with cheddar or mozzarella. Gruyère has the perfect melting properties and nutty flavour.