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Slow-cooker French onion soup recipe

Slow-cooker French onion soup recipe

26 ratings

Make the most of slow-cooker season! This French onion soup is so easy to make; simply bung in all your ingredients and let the slow-cooker do the work. See method

  • Serves 4
  • 4 hrs 00 mins
  • 386 calories / serving
  • Freezable

Ingredients

  • 800g thinly sliced onions
  • 50g unsalted butter
  • 2 tbsp caster sugar
  • 10g thyme sprigs
  • 1 bay leaf​
  • 1 tbsp plain flour
  • 1.4ltrs beef stock (made with 2 stock cubes)
  • 2 tbsp balsamic vinegar
  • 3 tbsp Worcestershire sauce
  • ¼ white baton
  • 75g finely grated Cheddar
If you don't have any Cheddar, try using another hard cheese

Each serving contains

  • Energy

    1610kj
    386kcal
    19%
  • Fat

    18g 26%
  • Saturates

    11g 57%
  • Sugars

    25g 28%
  • Salt

    2.9g 48%

of the reference intake
Carbohydrate 42.3g Protein 9.8g Fibre 5.5g

Method

  1. Preheat a 2ltr (or larger) slow-cooker for 5 mins. Add 800g thinly sliced onions, 50g unsalted butter, 2 tbsp caster sugar, 10g thyme sprigs and a bay leaf; stir, then cover and cook on high for 3 hrs (stirring every 1 hr, if possible) until the onions are soft and golden.
  2. Stir in 1 tbsp plain flour, then pour in 1.4ltrs beef stock (made with 2 stock cubes), 2 tbsp balsamic vinegar and 3 tbsp Worcestershire sauce. Cover and cook for a further 1 hr.
  3. Preheat the grill to high. Cut ¼ white baton into 4 thin slices and grill on a foil-lined rack on both sides until golden. Divide 75g finely grated Cheddar between the toasts, then grill again for 30 secs-1 min until golden and bubbling. Ladle the soup into warm serving bowls and top each with a warm cheese crouton.

Tip: Make this vegetarian by swapping in vegetable stock and using 1-2 tbsp soy sauce instead of Worcestershire sauce.

Tip: Keep in an airtight container in the fridge for up to 3 days, or freeze for up to 1 month.

Freezing and defrosting guidelines

In order to enjoy optimum flavour and quality, frozen items are best used within 3 months of their freezing date. For more tips on freezing and defrosting food, read our article Love Your Freezer.

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