For the lamb, mix the yogurt and turmeric, and brush it over each cutlet. Cut the aubergine into large wedges. Put a good slug of oil into a frying pan and fry the wedges on both side until they are browned all over and very soft (add more oil if you need to) – they should look almost translucent and lightly charred. Lift the wedges gently out of the pan with tongs, leaving the oil behind – if you have more than 1 tbsp oil left, pour some off.
Put the fennel seeds and nigella seeds in the pan and heat them until they start to pop. Add the coriander, turmeric and chilli, and let the oil foam up a little with the spices. Add the ginger and garlic, and cook for 1 min, making sure the mixture doesn’t stick. Tip in the tomatoes and simmer the mixture for 3 mins or until it starts to thicken, then season well. Return the aubergine to the pan to continue cooking.
Meanwhile, heat some oil in a frying pan. Salt the lamb cutlets on both sides and fry them until they are browned on the outside but still slightly pink inside. It’s important to make sure the fat is well browned. Spoon some yogurt over the curry and sprinkle with coriander leaves and nigella seeds. Serve with the lamb and chapatis or rice.