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Red Onion Soup With Melting Gruyere Croutons

After all the indulgence and expense of Christmas and the New Year, this hearty soup is the perfect antidote. Ideal for a warming winter lunch or
supper it’s simple to make, tastes delicious and doesn’t cost a fortune.

Serves 4 – Ready in 1½ hours

  • 2 tbsp olive oil
  • 15g butter
  • 650g small red onions, peeled and thinly sliced
  • 2 tsp brown sugar
  • 1 tbsp flour
  • 1 tbsp wholegrain mustard
  • 1.2litres beef or vegetable stock
  • Few sprigs fresh thyme, plus extra to garnish
  • Salt and freshly ground black pepper
  • 8 thin slices day old French bread
  • 75g Gruyere cheese, grated


  1. Heat the oil and butter in a large, deep heavy-based saucepan until the butter is sizzling. Add all the sliced onions and cook very gently over a low heat for 15 minutes, stirring frequently.
  2. Sprinkle over the sugar and cover and cook for a further 15-20 minutes, stirring occasionally, until the onions are very soft and golden.
  3. Stir in the flour and half the mustard and cook for 1 minute, then gradually stir in the stock. Add the thyme sprigs, season with salt and freshly ground black pepper (see Tip) and bring to the boil.
  4. Reduce the heat and simmer gently for 35-40 minutes, stirring occasionally. Adjust the seasoning to taste.
  5. Lightly toast the slices of French bread on one side. Spread the untoasted sides with the rest of the mustard and top with the grated Gruyere cheese. Pop under a hot grill for 1-2 minutes, or until the cheese is melted and bubbling.
  6. Ladle the soup into warmed bowls and top each with two hot Gruyere croutons. Serve immediately garnished with thyme sprigs.

TIP: If you use stock made up from stock cubes taste the soup before adding any seasoning as some can be quite highly seasoned.

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