Wash and clean the prawns. Add half of the ginger & garlic, chilli powder (half of it) & turmeric powder, kokum, thengakothu, salt & curry leaves to the prawns. Mix well using your hands. Add water and cook till it is done, make sure that prawns are not over cooked. Drain the excess water.

Heat oil in a pan and add finely sliced small onion and fry till it becomes golden brown. Add remaining ginger & garlic, curry leaves & onion. Saute till the onion becomes light brown. Add the remaining chilli powder, coriander powder & garam masala (if using) and fry till the raw smell goes and oil starts appearing. Add cooked prawns & salt (since prawns is already cooked with salt, adjust the salt for the gravy accordingly). Mix well and add 2-3 tbsp of water. Cook it till the water is dried and prawns are well coated with masala. I like the prawns to be roasted well, so I keep it for around 10-12minutes on low flame, by stirring it in between. Serve with rice or roti.