Prepare the marinade by mixing all the ingredients and marinate the fish pieces in this for at least one hour or as long as you can.
Shallow fry the fish pieces and keep aside.
Heat oil in pan and crackle mustard seeds. Add curry leaves along with ginger, garlic, onions, green chilli and sauté till the onions turn golden brown.
Then add all the spices and sauté till oil starts clearing.
Lower the heat and add second milk of coconut and mix well. To this add the fried fish pieces; season with salt. Cook for 5 minutes.
Next lower flame and add first milk of coconut to thicken the gravy and remove from fire. Do not boil or place or high heat or the coconut milk will split.
Garnish with curry leaves.