Start with the aubergines.
Heat the oil in a large pan. Add the diced aubergines, sauté for 1-2 minutes then add the coriander, turmeric, cumin, chilli, ginger, garlic. Cook for 3-4 minutes over a gentle heat. Add the tomatoes, vinegar, sugar and seasoning. Stir well and simmer for 20 minutes. Taste for seasoning.
To cook the lamb: Cut each rack in half. Season with salt, black pepper and balsamic. Set oven to Gas Mark 6, 200°C(400°F).
Heat a large ridged grill pan or other heavy pan. Put the four piece of lamb onto the pan. Brown well on all sides. Transfer the pan to the oven to finish cooking for15-20 minutes. When the lamb is cooked to your taste, remove it from the oven and set aside to rest for five minutes or so.