Dry fry cumin and mustard seeds in pan for a few minutes. Remove from heat and grind to form a powder.

Add the cumin and mustard seed powder to the mixed masala

In a large pot fry the onions in the oil with 2 sprigs of curry leaves. After a few minutes the onions will begin to turn slightly brown and transparent. At this stage add the masala and fry for a few seconds.

Add in the ginger and garlic paste and continue to fry.

The grated and sliced tomato may be added to the masala mixture. Allow this to simmer before stirring in the tomato puree and salt to taste.

The tomatoes should be completely melted before adding in the fish. Do not stir the curry as the fish will break.

Allow the curry to cook on a reduced heat for about 30 minutes. Stir the curry by gently shaking the pot ensuring that the fish is well coated with the fish gravy.

Add the garlic cloves and continue to cook. The fish curry will begin to have a distinctive aroma. At this stage stir in the tamarind. To prepare the tamarind place it in 50ml of water and remove pulp and seeds. Allow to cook.

Add in the green slit chilli, coriander and a sprig of curry leaf and simmer for a few seconds before removing the curry from the heat.