Mary Berry’s French Onion Soup Recipe

This Mary Berry French Onion Soup is a rich and classic recipe, which is made with sweet caramelized onions and cheesy Gruyère croûtes. It’s the ultimate comfort food recipe, ready in about 1 hour and 15 minutes.

Mary Berry French Onion Soup Ingredients

• 45 g (1 1/2 oz) butter
• 1 tbsp sunflower oil
• 1 kg (2 lb) large white onions, thinly sliced
• 2 tsp caster sugar
• 30 g (1 oz) plain flour
• 1.8 litres (3 pints) vegetable, chicken, or beef stock
• salt and black pepper
• 8 Gruyère croûtes

How To Make Mary Berry French Onion Soup

1. Caramelize the onions: Melt the butter with the oil in a large, heavy-based saucepan over a low-medium heat. Add the sliced onions and sugar. Cook slowly for about 20-30 minutes, stirring occasionally, until the onions are deep golden brown, soft, and sweet.
2. Thicken the soup: Sprinkle the flour over the caramelized onions and cook, stirring constantly, for 1–2 minutes.
3. Simmer the soup: Gradually stir in the stock, a little at a time, until smooth. Bring to a boil, then season with salt and pepper. Cover the pan, reduce the heat, and let it simmer gently for 35 minutes, stirring from time to time.
4. Serve: Taste the soup and adjust the seasoning if necessary. Ladle the hot soup into warmed, ovenproof bowls. Float a Gruyère croûte in each bowl and serve at once.

Recipe Tips

• How to properly caramelize onions? The key is patience. Cook the onions slowly over a low to medium heat. Don’t rush them on high heat, as they will burn and become bitter instead of sweet.
• How do I make Gruyère croûtes? Toast slices of baguette or French bread on both sides until golden. Top generously with grated Gruyère cheese and place under a hot grill for a few minutes until the cheese is melted, bubbling, and golden.
• What is the best stock to use? For the most traditional, richest flavour, use beef stock. However, chicken or a robust vegetable stock also work wonderfully.
• Can I use a different cheese? While Gruyère is classic for its nutty, salty flavour that melts beautifully, you could also use Comté, Emmental, or even a strong, sharp cheddar.

What To Serve With French Onion Soup

This soup is a hearty meal on its own, but a simple side can complete it.

• A simple green salad with a sharp vinaigrette dressing to cut through the richness.
• Extra crusty bread on the side for dipping.

How To Store French Onion Soup

• Refrigerate: Allow the soup to cool completely. Store it in an airtight container in the refrigerator for up to 3 days. Store the croûtes separately at room temperature.
• Freeze: The soup base (without the croûtes) freezes very well. Let it cool, then pour into freezer-safe containers for up to 3 months. Thaw overnight and reheat gently, preparing the croûtes fresh before serving.

FAQs

• Can I make this soup vegetarian? Yes, absolutely. Simply use a good-quality, flavourful vegetable stock to make a delicious vegetarian version of this classic soup.
• Why is my French onion soup bitter? This usually happens if the onions were cooked too quickly on high heat, causing them to burn rather than caramelize. The process should be slow and gentle to draw out the natural sugars.
• Can I make this soup ahead of time? Yes, it’s a great make-ahead dish. Prepare the soup and store it in the fridge. When ready to serve, reheat it gently on the stove while you prepare the fresh Gruyère croûtes.

Try More Recipes:

• Mary Berry’s Asparagus Soup Recipe
• Mary Berry Somerset Mushroom Soup Recipe
• Mary Berry French Pea Soup Recipe

Mary Berry’s French Onion Soup Recipe

Course: SoupsCuisine: British

Servings

8

servings

Prep time

15

minutes

Cooking time

1

hour 

Calories

353

kcal

A classic, rich, and deeply comforting soup made with slow-caramelized onions and topped with a cheesy Gruyère croûte.

Ingredients

• 45 g (1 1/2 oz) butter
  

• 1 tbsp sunflower oil
  

• 1 kg (2 lb) large white onions, thinly sliced
  

• 2 tsp caster sugar
  

• 30 g (1 oz) plain flour
  

• 1.8 litres (3 pints) beef, chicken, or vegetable stock
  

• salt and black pepper
  

• 8 Gruyère croûtes (toasted bread topped with grilled Gruyère cheese)

Directions

• Melt butter and oil in a large pan. Add onions and sugar and cook slowly for 20-30 minutes until deeply caramelized and golden.
  
• Stir in the flour and cook for 1-2 minutes.
  
• Gradually stir in the stock. Bring to a boil, season, then cover and simmer for 35 minutes.
  
• Taste and adjust seasoning.
  
• Ladle into bowls and top each with a fresh Gruyère croûte to serve.