Firstly grind everything given under " to grind for marination". Apply it over the clean and slit fish on both sides. marinate for 30 minutes to 1 hour.
Heat coconut oil for shallow frying and fry the fish on both sides until toasted.
Take it out to a plate and keep aside until use.
Heat coconut oil in another pan and fry the grated coconut until golden brown and add curry leaves and pepper powder. Mix well and strain it to a bowl until use.
In the same pan, coarsely grind onions, garlic, and green chilli and add to it. Fry until pale.
Season with salt, turmeric powder, chilli powder, coriander powder and fry well until raw smell leaves.
Pour in tamarind water. Mix well until thick.
Spread the masala all over the pan. Place the fried fish over the masala.
Gently pour in the coconut milk all over the fish and masala. Close and cook until the coconut milk is absorbed.
Open and pack the fish with the masala.
Wilt a banana leaf in fire and place the fish on it along with the masala.
Also, wither some fried coconut mix over it. Pack the banana leaf on all sides and secure it with a knot.
Place the packed banana leaf on the pan and cook it for 10 minutes on both sides.
Serve fresh and hot with sliced onions, tomatoes and lemon wedge.