1 large onion, peeled and chopped
1 large carrot, peeled and finely chopped
2 sticks of celery, trimmed and finely chopped
Salt and freshly ground black pepper
1kg lean minced lamb
250ml chicken stock
1 tbsp Worcestershire sauce
2 tbsp tomato puree
1 tbsp cornflour
1-2 tbsp tomato chutney (optional)
1kg sweet potatoes, peeled
2 tsp paprika
Meanwhile, melt the butter in a large saucepan on a low heat. Add the onion, carrot and celery and season with salt and pepper. Cover with a disc of greaseproof paper and a lid and cook for 8-10 minutes until soft but not browned.
Remove the lid and paper, add the minced lamb, increase the heat and cook, stirring regularly, for a few minutes until the meat changes colour. Pour in the stock and stir in the Worcestershire sauce and tomato puree. Bring to the boil, then reduce the heat, cover the pan with a lid and simmer for about 20 minutes or until the meat is fully cooked.
Place the cornflour in a small dish or cup and add a small amount of cold water. Stir the water and flour to form a smooth thick paste, adding more water a few drops at a time if needed. Pour the cornflour paste into the meat mixture and stir to thicken the sauce. Stir in the tomato chutney (if using).
Preheat the grill to high and the oven to 180°C. Pour the mixture into a pie dish and spoon over the sweet potato mash over the top, spread with a fork and grill for a few minutes to brown the potato slightly. Bake the shepherd’s pie in the oven for 20-25 minutes until hot and bubbling. Serve immediately.