1.Heat a quarter of the oil in large saucepan. Cook onion and seeds, stirring, until onion is soft. Remove from pan.
2.Heat remaining oil in same pan. In batches, cook combined lamb, ginger, garlic and paste until lamb is tender.
3.Return lamb to pan with onion mixture, yoghurt, crumbled stock cube and blended cornflour and water; stir over heat until mixture boils and thickens slightly. Keep warm.
4.To make mango relish, combine mango, coriander, vinegar and chilli sauce in a bowl; mix well.
5.Serve lamb curry with mango relish.