Shell prawns, de-vein and wash well. Peel yam, wash well and cut into pieces. Boil along with turmeric powder and salt until soft. Drain, wash again and mix with lemon juice. Keep aside.
Blanch prawns for a few minutes and then grind into a fine paste. Peel and chop onion, ginger and garlic. Grind together. Chop green chillies and coriander leaves finely.
Beat the egg. Heat two tablespoons of oil, add ground onion paste, green chillies and coriander leaves and cook for a while. Add prawn paste and cook briefly.
Add yam, adjust salt and continue cooking until mixture dries. Take off the heat and divide into small equal portions. Shape each portion into heart shape.
Dip into beaten egg and coat with breadcrumbs. Again form into heart shapes. Deep fry cutlets. Serve preferably with date chutney.