Wash and scale the fish. Then cut it in to four pieces (4-5 oz for each piece). Marinate for 30 minutes with 1 tsp turmeric and 1 tsp salt. Heat the oil in high heat then simmer. Pat the marinated fish with kitchen towel to dry them. Carefully place them in to the hot oil. Let the underside fry to light brown. Then use a spatula to flip it and fry the other side, also to a light brown color. Take out the fried fish in a bowl. In the same oil add sugar and let it caramelize. Now add cumin seed, bay leaf, and sauté for 30 seconds. Then add onion paste, ginger garlic paste, tomato purée, green chili, yogurt, turmeric, garam masala, cumin powder, and salt. Mix and sauté for 5 minutes in medium heat. If it looks dry add 1-2 tsp water. When you notice the oil separating from the mixture and starting to float on top, add 1 cup hot water and the fried fish. Let them cook for 4-5 minutes. Adjust the consistency of the gravy as per your choice (if you prefer a thinner gravy, add some more water).
It is ready to be served with Bashonti Pulao!
Note: This is also a very versatile recipe. Using the same recipe, you can cook any kind of fish, including lobster and crab. You can add potato, cauliflower, peas to the kalia as well. You can even make it vegetarian / vegan by using tofu or paneer instead of fish!