French onion soup

Introduction

French onion soup is a dark, sweet soup of slowly caramelised onions, topped with toasted bread and melted cheese and finished under the grill. It turns the cheapest vegetable there is into a rich winter dinner. It takes time, but hardly any work.

Onion soups are old peasant food all over Europe. The version with a cheese crust became famous in Paris, where it was served through the night to the market workers of Les Halles and the people going home after a night out. The traditional broth is beef stock; a good vegetable stock and a spoon of soy sauce give the soup depth and keep it vegetarian. Many cheeses such as Gruyère use animal rennet, so check the label if that matters to you.

Ingredients

• 50 g butter
• 1 kg onions, thinly sliced
• 1 teaspoon sugar
• 1 tablespoon flour
• 150 ml dry white wine
• 1.2 litres vegetable stock
• 1 teaspoon soy sauce (optional, for depth)
• 2 sprigs of thyme and 1 bay leaf
• salt and black pepper
• 8 slices of baguette
• 150 g Gruyère or Comté, grated

Tools

• A large heavy pot
• A wooden spoon
• An oven with a grill, and 4 ovenproof bowls (or a baking tray)
• A grater

Preparation

1. Melt the butter in the pot over a medium heat. Add the onions and a good pinch of salt, stir, cover and cook for 10 minutes, until they soften.
2. Uncover, add the sugar and cook on a medium-low heat for 40 to 50 minutes, stirring every few minutes and scraping the bottom, until the onions are a deep brown. If they catch, add a splash of water and scrape.
3. Stir in the flour and cook for one minute. Pour in the wine and let it bubble for 2 minutes, scraping the bottom.
4. Add the stock, soy sauce, thyme and bay leaf. Simmer for 20 minutes. Season with salt and pepper and remove the herbs.
5. Meanwhile, toast the baguette slices under the grill.
6. Ladle the soup into the ovenproof bowls, float two slices of bread on each and cover with cheese. Put them under a hot grill for 3 to 5 minutes, until the cheese bubbles and browns. Without ovenproof bowls, grill the cheese on the bread on a tray and put it on the soup.