1.5kg leg of lamb on the bone
5cm root ginger, peeled and grated
1 onion, finely chopped
4 tbsp natural yogurt, whisked
4 tbsp sunflower or vegetable oil
1 tsp garam masala
1/2 tsp chilli powder
1/2 tsp salt

Prick the flesh of the lamb all over with a skewer or sharp knife. Put the ginger, onion, yogurt, oil, garam masala, chilli powder and salt in a large bowl and mix well.

Add the lamb to the bowl and use use your hands to smear the marinade all over the lamb, then cover and place in the fridge for at least 1 hour, or overnight if time allows. Remove the lamb from the fridge 20 minutes before cooking.
Preheat the oven to 180C/350F/Gas 4.


Put the lamb in a roasting tin, cover with foil and roast for 2 hours. Baste with the juices in the tin after 1 hour, then continue roasting for the remaining 1 hour, or until the flesh is tender when you pierce it with a fork.
Remove the lamb from the oven and leave to rest, still covered with the foil, for about 15 minutes before carving and serving.