Brown the lamb shoulder and cumin seeds in half the oil using a large pan.
Fry onions, ginger, garlic, chilli, and spices in two tablespoons of oil.
Add lamb and stock to the pan, cover, and simmer for 150 minutes until tender.
Blend ginger and garlic, then mix with oil, yoghurt, lime juice, and zest.
Coat lamb racks in the paste and marinate for at least 60 minutes.
Skewer and roast lamb racks in a tandoor oven for 15 minutes, then rest.
Steam potatoes for 25 minutes, then combine half-grated and half-crushed textures.
Mix cumin, chilli, garlic, and coriander into potatoes and shape into four cakes.
Fry the potato cakes in butter and oil until lightly browned.
Roast cumin, garlic, ginger, chilli, and onion in oil for several minutes.
Add turmeric, aubergine, and lemon, then cook slowly for 20 minutes before adding coriander.
Strain and blend the lamb shoulder sauce, then re-warm the meat in it.
Blend mint, coriander, chilli, garlic, lime, and sugar with oil into a smooth chutney.
Plate the aubergine, potato cakes, chutney, roasted rack joints, and braised shoulder.