Clean your fish fillets and marinate the fish with the lime juice, salt and vinegar for 30mins

As it is marinating, add the grated coconut, ginger, garlic, and tomatoes. Without adding any water, process this for a few minutes

Heat some oil in a deep cooking pot and add the mustard seeds. Once it starts popping, add the onions and fry until they are soft, then add the curry leaves and sauté

When the onions turn brown, add the three masala powders: Coriander, Tumeric and Chilli. Stir-fry for a minute

Add the coconut mixture, and sauté for 3-4mins, stirring constantly. Next add the coconut paste, some salt and about 2 cups of water and bring to a boil and simmer for 3mins

Gently lay the fish fillets in a single layer and reduce the heat to low. Sprinkle the cumin and fenugreek seeds over the fish and cook until the fish is done

If you let the fish curry is left to sit for a few hours before serving, the flavour will seep into the fish. Serve hot with rice!