Slow-cooker French onion soup recipe

Name: Slow-cooker French onion soup
Yield: Serves 4
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

Created by The Tesco Recipes team

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 hours to cook
386 calories / serving

Freezable

Shop your ingredients

Tesco Brown Onions Loose
800g thinly sliced onions
£0.11
£0.95/kg
Tesco British Unsalted Butter 250G
Aldi Price Match
50g unsalted butter
£1.85
£7.40/kg
Silver Spoon Caster Sugar 1Kg
2 tbsp caster sugar
£2.25
£2.25/kg
Tesco Fresh Cut Thyme 20G
Aldi Price Match
10g thyme sprigs
£0.50
£25.00/kg
Tesco Bay Leaves
1 bay leaf
£0.80
£0.08/each
Stockwell & Co. Plain Flour 1.5Kg
Aldi Price Match
1 tbsp plain flour
£0.70
£0.47/kg
Tesco Beef Stockpot 4 Pack 112G
1.4ltrs beef stock (made with 2 stock cubes)
£1.45
£12.95/kg
Tesco Balsamic Vinegar Of Modena 250Ml
2 tbsp balsamic vinegar
£1.65
£6.60/litre
Tesco Worcester Sauce 150Ml
3 tbsp Worcestershire sauce
£1.30
£8.67/litre
H.W. Nevill's Part Baked White Baguette 2 Pack
Aldi Price Match
¼ white baton
£0.85
£0.42/each
Creamfields Mature Grated Cheddar 250g
Aldi Price Match
75g finely grated Cheddar
£1.89
£7.56/kg

Method

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.
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.
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.

See more Soup recipes

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.