1.Clean the fish and put cuts on the fish and keep aside.
2.In a pan add little oil splutter mustard seeds and fenugreek seeds.
3.Add sliced onions and sliced shallots and saute well.
4.When the onions start changing the color and finely chopped ginger and garlic.
5.Saute well and add the coriander powder,turmeric powder,red chilly powder and pepper powder and mix well.
6.Add the chopped tomatoes and mix well till the tomatoes are soft.
7.Add the tamarind pulp,salt and mix well.
8.Add the thick coconut milk and curry leaves and mix well.
9.Let it boil for some minutes in simmer till u get a thick gravy.
10.Now wash the banana leaves dry it and just soften it by putting it up on an open flame.(Ila Vattal).
11.Then as seen in the above picture Put some masala on the leaf and place the fish over the masala.
12.Cover the fish with masala and fill it inner portion also with some masala.You can add some more curry leaves now.
13.Now cover the fish with the banana leaf and tie with some thread to make a packet.
14.Now heat a mud chatti or in a tawa spread some coconut oil and place this packet carefully over the tawa and close with a lid.
15.Cook on a medium flame each sides for 10 mins.
16.Serve hot with plain rice,kubus or chapathis.