Marinate the fish slices with ginger garlic paste, 1 tsp of chilli and coriander powder, 1/2 tsp turmeric powder, 1/2 tsp pepper and salt. Sprinkle the marinated fish slices with rice flour. set aside for 5-10 minutes
Meanwhile, slice the onions ginger and garlic. Measure out the coconut milk. I used canned coconut milk.
In a thick bottom frying pan, start frying the fish slices in oil on a medium-high flame . fry each side only for couple of minutes . They will continue cooking in the gravy later. Fry these in batches and set aside
After all the fish slices have been fried, add some more oil to the same pan (less washing up ☺️) and add the sliced onions, ginger and garlic. Fry until they are soft and beginning to turn brown.
Reduce the flame to low and add the remaining chilli, coriander and turmeric powders. Stir to mix well and cook for couple of minutes.
Add 1 cup of water & mix well with the fried onion mixture. Bring this to a simmer.
Now add the fish tamarind, salt and some more pepper and mix. Once this is mixed nicely, gently add the fried fish slices. Simmer for 5-10 minutes and add the coconut milk. Do not boil the coconut milk, let it gently simmer for couple more minutes.
Switch off the flame and let the curry rest for atleast 10 minutes. Garnish with some fresh curry leaves and sliced green chillis for an added burst of flavour.