French onion soup

Classic French Onion Soup

There’s nothing quite as comforting as a steaming bowl of French Onion Soup on a chilly evening. This beloved bistro classic features sweet, caramelised onions swimming in a rich beef broth, topped with toasted bread and melted Gruyère cheese. It’s the kind of dish that looks impressive but is surprisingly straightforward to make at home. Whether you’re planning a dinner party or simply craving some authentic French comfort food, this recipe will transport you straight to a Parisian bistro.

This recipe makes approximately 2.5 litres of soup, which serves 4-6 people generously (about 400-600ml per serving).

Prep time: 15 minutes
 Cook time: 1 hour 15 minutes
 Servings: 4-6
 Difficulty: Easy

Ingredients

  • 6 large yellow onions, thinly sliced
  • 60g unsalted butter
  • 2 tablespoons olive oil
  • 1 teaspoon sugar
  • 2 cloves garlic, minced
  • 2 litres quality beef stock
  • 240ml dry white wine
  • 2 bay leaves
  • 1 teaspoon fresh thyme (or ½ teaspoon dried)
  • Salt and freshly ground black pepper to taste
  • 1 baguette, sliced into 2.5cm rounds
  • 200g grated Gruyère cheese (or a mix of Gruyère and Emmental)
  • Fresh thyme sprigs for garnish (optional)

Method

  1. Caramelise the onions: In a large, heavy-bottomed pot or Dutch oven, melt the butter with the olive oil over medium heat. Add the sliced onions and stir to coat. Sprinkle with the sugar (this helps with caramelisation). Cook, stirring occasionally, for about 40-45 minutes until the onions are deeply golden and caramelised. Don’t rush this step! The sweet, rich flavour of the soup depends on properly caramelised onions.
  2. Add the garlic: Once the onions are beautifully caramelised, add the minced garlic and cook for another 1-2 minutes until fragrant.
  3. Deglaze and simmer: Pour in the white wine, scraping up any browned bits from the bottom of the pot. Let it bubble for 2-3 minutes to cook off the alcohol. Add the beef stock, bay leaves, and thyme. Season with salt and pepper. Bring to a boil, then reduce heat and simmer for 20-25 minutes to allow the flavours to meld.
  4. Prepare the bread: While the soup simmers, preheat your oven to 180°C (Gas Mark 4). Arrange the baguette slices on a baking tray and toast for about 10 minutes until golden and crisp on both sides.
  5. Assemble and grill: Preheat your grill to high. Ladle the hot soup into oven-safe bowls. Top each bowl with 2-3 toasted baguette slices and generously cover with grated Gruyère. Place the bowls on a baking tray and put under the grill for 3-5 minutes until the cheese is melted, bubbly, and golden brown on top.
  6. Serve: Carefully remove from the oven (the bowls will be very hot!). Garnish with a sprig of fresh thyme if desired. Serve immediately while the cheese is still gooey and the soup is piping hot.

 

Serving Suggestions

French Onion Soup makes an excellent starter for a dinner party. You could follow it with duck confit as a main course, or serve it alongside one of our French pâtés and terrines for a lighter meal.

For more inspiration on putting together a complete French menu, check out our guide to 7 Essential French Appetisers For A Dinner Party.

Chef’s Tips

If you want to make this soup even more luxurious, try adding a splash of cognac or brandy along with the wine for extra depth. The soup base (before adding the bread and cheese) can be made a day ahead and reheated when you’re ready to serve. The flavours actually improve overnight! Just save the toasting and cheese grilling for right before serving.

Store any leftover soup (without the bread and cheese) in an airtight container in the fridge for up to 3 days. You can also explore more of our French recipes for other bistro classics to add to your repertoire.

Bon appétit!

 

  • Prep time15 minutes
  • Cook time1 hour 15 minutes
  • Servings4-6
  • Difficultyeasy