Grind both pastes and beat the yogurt first. Then, marinate the fish pieces with salt, and set them aside for 10 minutes.
Heat 2 tbsp of refined oil in a wok on a medium flame.
Fry the chopped onions until they turn dark brown.
Take out the fried onions and place them on a plate. They will be used as beresta.
Take another pan and heat 1 tbsp of refined oil in it on a medium flame.
Fry the fish for about 2 to 3 minutes per side until golden brown on both sides, and then transfer them to a plate. (Pro Tip: Do not over-fry the fish because it can make it crispy and less juicy).
Add the whole spices such as bay leaf, cardamom, cloves, cinnamon and give them a good stir for about 10 seconds.
Add the ginger-garlic-onion paste and mix well.
Add ¼ tsp of salt.
Add the cashew-raisin paste.
Add half of the beresta (fried onions), stir well and cook until oil starts to separate.
Reduce the flame to low. Add yogurt and mix well. (Pro Tip: Stir continuously because it will prevent the yogurt from curdling).
Add 1 cup of warm water for the desired gravy consistency.
Once the water comes to a boil, add the fried fish. Simmer for about 5 to 6 minutes. (Pro Tip: Once the fish is added, let it simmer gently and avoid frequent stirring to keep the pieces intact).
Sprinkle the shahi garam masala.
Add the ghee for a royal flavor.
Turn off the stove. Sprinkle the remaining beresta (fried onions) and your tasty homemade Fish Korma is ready.