In a pan dry roast grated coconut and coriander seeds, and let it cool
Meanwhile add little oil and saute sliced onion till nice golden when cool, blend it to make a smooth paste add water if required. In a kadhai add oil when heated add the ground masala, chilly powder, cut the potatoes and add to the masala mix well
When patotoes are 1/2 done, add brinjals add water if required, when brinjals are 1/2 done add prawns, kokam and garam masala let it simmer of 8-10 mins.