Grind the onion, garlic and curry leaves very coarsely.

Soak the tamarind in a cup of water.

Extract the juice from the tamarind.

Pour the tamarind juice in a bowl.

Add the grinded mixture, chilli powder, turmeric powder, and salt and mix it well.

In a heated pan add oil and add vadavam or mustard seeds.

When it splutters add the kozhambu mixture and close it with a lid.

Boil it for 5-8 minutes and remove the lid and add the fish and cook it for 5 more minutes.

Then heat the kozhambu till it gets thick.