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Soups · French

French Onion Soup

An hour of patient browning, deglazed with splashes of water, under a lid of toasted bread and bubbling Gruyère.

Prep
15 min
Cook
1 hr 35 min
Total
1 hr 50 min
Serves
4

Added .

Illustration of french onion soup

Why this version

  • Starting the onions covered for 15 minutes softens them quickly and cuts total cooking time.
  • Deglazing with a few tablespoons of water whenever the pan browns gives deep colour without burning.
  • A mix of beef and chicken stock was the best balance between richness and saltiness.

Ingredients

Servings
4 servings
Units
  • 1.5 kg yellow onions, halved and thinly sliced
  • 50 g unsalted butter
  • 1 tbsp olive oil
  • 1 tsp fine salt
  • 2 garlic cloves, finely chopped
  • 1 tbsp plain flour
  • 120 ml dry white wine
  • 1.2 litres beef or mixed beef and chicken stock
  • 3 thyme sprigs
  • 1 bay leaf
  • 2 tbsp brandy, optional
  • 8 baguette slices, about 2 cm thick
  • 200 g Gruyère or Comté, grated

Method

  1. Melt the butter with the oil in a large, heavy pot over medium heat. Add the onions and salt; it will look like far too much, but they collapse. Cover and cook for 15 minutes, stirring twice, until soft and sitting in their own liquid.

  2. Uncover and cook over medium-low heat for 50–60 minutes, stirring every 5–10 minutes. Whenever a brown layer forms on the bottom, add 2–3 tbsp water and scrape it up. Keep going until the onions are a deep chestnut brown and jammy.

  3. Add the garlic and flour and stir for 2 minutes. Pour in the wine, scrape the pot well and simmer until almost evaporated.

  4. Add the stock, thyme and bay leaf and simmer for 20 minutes. Remove the herbs, season to taste and stir in the brandy if using.

  5. Meanwhile, toast the baguette slices in a 180°C oven for about 10 minutes, until dry and crisp.

  6. Heat the grill to high. Ladle the soup into ovenproof bowls set on a tray, float two toasts on each, and pile on the cheese, covering the edges. Grill for 3–5 minutes until bubbling and spotted brown.

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What we tested

  • A pinch of baking soda to speed up browning: faster, but the onions turned mushy and slightly soapy.
  • Slow cooker, 10 hours on low: deep colour, but none of the roasted notes from the pot.
  • Water instead of stock, with soy sauce and a little Marmite: surprisingly good, and the base of our vegetarian version.

Keeping

The soup, without the bread and cheese, keeps for 4 days and freezes well. The browned onions alone freeze for 3 months.

Swaps and notes

Vegetarian: use vegetable stock with 1 tbsp soy sauce and 1 tsp yeast extract, and a vegetarian cheese.

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