Heat half the oil in a pan.

Add coriander seeds, fenugreek seeds, fennel seeds and red chillies.

Saute for 5 mins, until chillies begin to go dark in colour.

Add onions and fry, stirring constantly, for about 8 mins.

When the onions are soft, remove the mixture and spread on a tray to cool.

When cool, grind it to a very fine paste along with tamarind pulp and a little water, if necessary. Keep it aside.

Heat the remaining oil in a deep frying pan.

Splutter mustard seeds.

Add curry leaves, garlic and turmeric.

Add the ground onion paste and stir well.

Add water to make a sauce consistency.

Add jaggery and salt and mix well.

Bring the contents to a boil.

Remove any scum from the surface with a slotted spoon.

Add the fish pieces.

Cook for approximately ten mins, until the fish is cooked.