To roast and grindHeat 1 tsp oil in a heavy bottomed pan,add the grated coconut and fry stirring continuously over medium flame until it turns golden brown. Reduce the flame to low and add the kashmiri chilli powder,coriander powder and turmeric powder.Fry for about 1 minute stirring continuously to avoid burning.Switch off the stove.Immediately transfer this into a plate and allow to cool completely. Transfer the coconut mix into a blender jar.Grind to form a smooth paste.(If you are not able to grind it, add 1 or 2 tbsp of water as required.)Set aside until required.
Wash and soak the tamarind in 1/2 cup water for about 5 minutes.In a pan/manchatti add the prawns,turmeric powder,few curry leaves,salt and fish tamarind along with the soaked water.Cook for about 5 to 8 minutes over medium flame.
Add the roasted coconut paste to the prawns.Add sufficient quantity of water and bring it to a boil.
Meanwhile heat 1 tbsp oil in a pan,add the mustard seeds and let it splutter.Add the curry leaves,coconut bits,shallots,ginger,garlic and green chilies.Add salt as required.Saute until the shallots turn golden brown over medium flame.
Add this to the prawn curry and boil for another 5 minutes or until the gravy turns thick.Serve with rice.