Grind the whole spices and add to the turmeric and chilli powder. Thoroughly coat the meat with the spices and leave to marinade for at least a couple of hours (preferably overnight in the fridge).
Heat the oil or ghee in a large pan – it must be very hot. Add your lamb in batches (it will spit everywhere so take care) and turn in the fat to brown it. Turn the heat down and add the brown stuff.
Cover and simmer for 60 minutes until the meat is tender. Stir in the cream and garam masala, and remove from the heat. Just before serving, stir in the chopped fresh coriander.