Take 1 kg of Katla fish (cut into large pieces), wash them nicely, dry them and keep on a plate. Mix 1 tsp of turmeric powder, ½ tsp of red chili powder, and 1 tsp of salt on every piece nicely with your hand and keep the plate aside for about 10 minutes to marinate.

Then, heat 4 tbsp of mustard oil in a kadai over a high flame. When hot, reduce the flame to medium and put the fish pieces, leaving enough space in between two pieces. Flip very carefully when one side is fried well. Remove them in a separate bowl when both sides are fried nicely and keep them aside. Repeat the process to fry all the fish pieces.

In the same oil, put in 4 pieces of green cardamom (whole pods), 1 piece of cinnamon (half-inch stick), 2 pieces of cloves, 2 pieces of bay leaves (torn in half), and 2 pieces of dry red chilies (whole, without stalk). Sauté them for about 10 seconds. Then, add 1 cup of onion paste (3 medium-sized onions) to it. Stir continuously and fry on a low to medium flame until the raw smell of the onion is gone and it turns slightly golden brown in color.

At this stage, put in 1 tbsp each of garlic paste, ginger paste, and cumin paste followed by ½ tsp of coriander powder, 1 tsp of red chili powder, 1 tsp of Kashmiri red chili powder, and ½ tsp of turmeric powder. Add a little bit of water and mix everything nicely. Stir and cook nicely on a low flame for about 7 to 8 minutes until it releases oil.

Now, add 2 tbsp of whisked curd, 2 tbsp of cashew nut paste, 1 piece of tomato (small size, cut into small pieces), 1 tbsp of raisin paste, salt to taste, and 1 tsp of sugar to it and mix well. Cook the masala for another 10 to 12 minutes or so on a low flame. Now, pour 2 cups of water and mix nicely. Let it cook for a couple of minutes until the water comes to a boil. At this stage, add the fried pieces of fish to it one by one very carefully. Mix and let it cook for another 6 to 7 minutes on a medium flame.

Finally, add 1 tsp of garam masala powder and ½ tbsp of ghee (clarified butter) to it. Switch off the flame of the gas stove, and cover the kadai and let it sit for 5 to 6 minutes to let the flavor of ghee and garam masala infuse properly with the fish kalia.

After 5 minutes, remove the cover, give it a nice mix. Your tasty and spicy homemade Katla macher kalia is now ready. Transfer it to a plate and serve with steamed rice.