Take 3 pieces of fish (Katla) in a kadai and add 1 tsp of ginger garlic paste, ½ tsp of salt, 1 tsp of black pepper powder, 1 tsp of lemon juice, and ½ cup of water. Cover and cook the fish pieces for 5 to 6 minutes on a low flame to boil them perfectly. (Pro tip: You can use any fish type with less bones instead of Katla).
Transfer the boiled fish pieces on a plate, remove the bones, and mash them with your hands nicely.
Now, to make the kofta mixture, add 1 piece of onion (small, chopped finely), ½ tsp of shahi garam masala powder, 1 tsp of cumin powder, ¼ tsp of turmeric powder, 1 tsp of Kashmiri red chili powder, ½ tsp of coriander powder, a handful of finely chopped coriander leaves, and 2 pieces of potatoes (small size, boiled, peeled, crushed) to the mashed fish and mix everything nicely. Then, to the mixture, add 1.5 tbsp of corn flour, salt to taste, and crack one egg and mix them nicely.
Heat an adequate amount of cooking oil in a frying pan on a medium flame. While the oil heats up make the kofta balls put them in the oil when done. Flip carefully and fry them until golden brown. Remove them on a plate and keep aside.
Now, to make the gravy, transfer the remaining oil into a kadai and put ½ tsp of cumin seeds, half a piece of mace (torn into small pieces), 1 piece of cinnamon (1-inch stick, broken in half), 5 pieces of cloves, and 2 pieces of green cardamom when the oil heats up. When you smell the aroma of the fried spices, add a piece of onion (small, finely sliced) and fry it on a medium flame until it turns slightly brown.
In the meantime, in a mixer, take 1 piece of onion (medium size, diced roughly), 2 pieces of green chilies, 3 cloves of garlic (deskinned), and 1 piece of tomato (medium size, diced roughly). Make a smooth paste.
Now, put the masala paste and mix it with the onions and fry for about a couple of minutes on a medium flame.
Then, add ½ tsp of turmeric powder, ¼ tsp of shahi garam masala powder, 1 tsp of cumin powder, 1 tsp of Kashmiri red chili powder, and ½ tsp of coriander powder. Mix them nicely. Then, add salt to taste, 1 tsp of sugar, ¾ cup of warm water to it and mix nicely. Cook for another 2 minutes.
When the gravy boils, add the fried fish kofta balls and mix nicely. Let them cook for another 3 to 4 minutes on a very low flame. Finally, add ¼ tsp shahi garam masala and ½ tsp of ghee (clarified butter) to it.
Your tasty and spicy homemade fish kofta curry is ready to enjoy. Transfer it to a serving bowl along with steamed rice, pulao, fried rice, or paratha.