Wash the fish and drain thoroughly.
Dry roast the whole spices for the spice paste in a skillet on medium heat for about 2 minutes, till fragrant.
Switch off the heat, cool and stir the turmeric powder into the hot spices. Grind to a fine powder.
Add the green chillies, ginger, onion and rice flour and grind again to a fine consistency…
Heat oil in a deep pan or wok on medium heat. When hot, sauté the onions, ginger and green chillies for about 1-2 minutes, till the onions are lightly browned.
Add the ground spice paste and tamarind paste and continue to sauté on low heat for another 1-2 minutes. Add the thick coconut milk, fish pieces and season with salt. Simmer for 5-8 minutes or till the fish is tender.
Add lime juice and coriander leaves, mix and remove immediately from heat.
Serve hot with plain, boiled, white rice and pappadums.