Method:

1. Use a mortar and pestle to pound the dry red chilies into a coarse paste using a teaspoon of water.

2. Squeeze the soaked tamarind well to release all the pulp from it. Strain the thick tamarind juice and discard the pith and seeds. 

3. Mix the red chili paste and tamarind juice with the ground coriander and turmeric and add salt to taste. Then add the grated coconut and half the coconut milk. Mix well.

4. Place the pieces of fish in a large, flat dish and pour the mixture over it to cover. Make sure all the pieces are coated and marinate for 3 hours. 

5. Heat the cooking oil in a deep pan over a medium flame until hot. Add the curry leaves, fenugreek seeds, green chili. Fry for roughly 2 minutes, or until the oil stops splattering.

6. Now add half the onion paste. Fry until the onion begins to brown very slightly. 

7. Add the chopped tomato. 

8. Fry till the spices start to release their oil and tomato turns darker. Stir frequently while frying. 

9. Now add the fish marinade and stir.

10. Bring to a boil over medium heat. Add the garlic paste, pepper, cumin, remaining onion paste, and remaining coconut milk. 

11. Lower to a simmer and cook until oil begins to appear on top of the gravy.

12. Add the pieces of fish and simmer until cooked through. If stirring, do so very gently to avoid breaking the pieces of fish. 

13. Turn off heat.

14. Serve curry on top of hot steamed basmati rice and enjoy!