Hairy Bikers' Cottage Pie - Quids in! magazine

Ingredients

• 400g lean minced beef
• 2 medium onions, chopped
• 2 celery sticks, finely sliced
• 2 medium carrots, diced
• 400g can of chopped tomatoes
• 2tbsp tomato purée
• 500ml beef stock, made with 1 beef Stock cube
• 1tbsp Worcestershire sauce
• 1tsp dried mixed herbs
• 4tsp cornflour
• 1tbsp cold water
• Flaked sea salt
• Freshly ground black pepper
• 750g floury potatoes
• 2tsp sunflower oil
• 2 slender leeks, trimmed and cut into 1cm slices
• 150g half-fat crême fraiche