Ingredients
Method
1.Gently bash cardamom pods with a mallet and extract seeds. Put cardamom and cumin seeds, whole cloves and peppercorns in a small dry frying pan and toast over a medium heat for a few minutes until fragrant.
2.Blend garlic, ginger, toasted spices, lemon juice, oil, salt, chilli powder and turmeric to a paste in a blender.
3.Prick lamb all over with a sharp skewer and, using a sharp knife, make a dozen or so slashes in the meatier parts of the meat on both sides of the leg. Put lamb in an ovenproof dish and massage with the spice paste.
4.Blend pistachio nuts and almonds together in a blender with 2 tablespoons brown sugar and enough yoghurt to stop blender from stalling, then mix in remaining yoghurt. Spoon over lamb. Cover and refrigerate for 48 hours.
5.Bring lamb to room temperature 1 hour before cooking. Preheat oven to 180°C. There should be some liquid around the lamb; if not, pour ¼ cup water around (not over) the meat.
6.Sprinkle remaining 1 tablespoon brown sugar on top of lamb. Cover with baking paper then tinfoil (or a lid) and bake for 1½ hours.
7.Remove foil and paper and baste well. Increase oven temperature to 200°C and when up to speed return lamb to oven and cook for a further 15 minutes or so, until it is a gorgeous golden brown. (If you like lamb more well done, cook for 2 hours before browning.) Rest lamb for 15 minutes before slicing.
Ask your butcher to cut through the lamb shank bone so it will easily fit in a regular roasting tin.
Note