French Onion Soup
Slow-caramelized onions in a rich broth, topped with toasted bread and melted cheese. A warm, comforting bowl made from humble ingredients. The soup started life as Parisian market food — onions were the cheapest thing going, and a pot of broth could be kept going all night for the workers at Les Halles. Everything about its flavour comes from that long, patient caramelization, because onions are more than half sugar waiting to be coaxed into colour.
Prep time15 min
Cook time45 min
Total time60 min
Servings4 servings
DifficultyMedium
Ingredients
- 5 large onions, thinly sliced
- 3 tbsp butter
- 1 tbsp olive oil
- 1 tsp sugar
- 3 tbsp flour
- 6 cups beef stock
- 1/2 cup white wine (optional)
- 2 bay leaves
- Salt and black pepper
- 4 thick slices of baguette
- 150g gruyère or mozzarella, grated
Instructions
- 1Melt the butter and the oil in a large heavy pot over medium-low heat. Add the onions and the sugar and stir well so every slice is coated in fat.
- 2Cook gently for 25-30 minutes, stirring every few minutes and scraping the bottom of the pot. If the onions begin to catch or look dry, add a splash of water — never turn up the heat to speed things along.
- 3When the onions are a deep mahogany brown and reduced to a soft tangle, stir in the flour and cook for a full minute until the raw floury smell disappears.
- 4Pour in the wine, if using, and scrape the bottom of the pot clean. Let it bubble for a minute so the alcohol cooks off.
- 5Pour in the stock, add the bay leaves and season lightly. Simmer gently for 15 minutes, then taste and adjust — the broth should taste sweet and deep, never thin or watery.
- 6While the soup simmers, toast the bread slices until they are crisp right through, so they can hold up the cheese without collapsing.
- 7Ladle the soup into ovenproof bowls, float a slice of toast on each, then cover generously with the grated cheese right to the rim.
- 8Grill or bake for 3-5 minutes until the cheese is bubbling and golden in patches. Serve hot, and warn people about the bowls.
Tips
- Don't rush the onions — the deep golden colour is where all the flavour is.
- A splash of wine or a spoon of Worcestershire sauce adds depth.
- Use ovenproof bowls so the cheese topping can melt under the grill.
- Slice the onions to an even 3mm or so. Uneven slices colour unevenly, and any that are too thin will scorch before the rest are ready.
- The soup base freezes well without the topping for up to 2 months. Add the toast and cheese only when you reheat it.
