Fry the lamb in the oil in batches and tip it into the slow cooker. Fry the onion in the same pan for 5 mins or until it softens a little. Add the carrots and spices, stir everything together, add the tomato purée, stock and 250ml water and swirl everything around the pan. Tip into the slow cooker. Add the sweet potato, dried cherries, honey and another 500ml water.
Cook on low for 8 hrs or high for 4 hrs. Stir in the coriander and serve with couscous. Leave to cool before freezing.