Take a vessel and put fish pieces, chopped ginger, onion, green chillies, coriander leaves, turmeric powder and required salt.
Pour 1/2 cup water into the fish pieces and boil. Simmer in medium heat.
After the fish pieces are cooked, sieve and collect the fish stock. Crush the cooked fish. Keep the stock aside.
For preparing ground mixture, grind turmeric powder, chilly powder, coriander powder, garlic, ginger, shallots, pepper powder and cummin seeds. Keep this ground mixture aside.
Into the cooked and roughly crushed fish pieces, add yolk of one egg, crushed bread slice, pepper powder, maida and oil. Mix together and make small lime sized balls.
Take a frying pan and pour oil. Heat oil and beat the egg white. Dip the fish balls in egg white and fry until golden. Repeat with all fish balls.
In the remaining oil, fry sliced onion, slit green chillies and curry leaves.
Pour the ground mixture into the oil and fry until a frying smell comes.
Now pour the fish stock, tamarind water, sugar and required salt. Boil the mixture.
When boiling starts, lower the flame and dip the fried fish balls one by one.
Close the pan with a lid and simmer in low heat until the gravy acquires a thick consistency.
When oil accumulates on top, remove the pan from fire.
Yummy fish kofta is ready and serve hot.