Bengali style Bombay duck curry

1) Immerse the dried fish in water for 5 mins, wash and pat dry the fish pieces. Rub with a pinch of salt and the turmeric and leave for 15 minutes.
2) Crush the ginger, garlic and green chillies with a pestle and mortar to make a paste.
3) Meanwhile, heat the mustard oil in a saucepan. When its smoking, add dried red chillies, whole spice and cumin seeds to release the flavours.
4) Add the onion and cook for 2 minutes.
5) Add the ginger paste. Fry well for 2 minutes on a high heat. Add the rest of the spices and 4 tbsp. of water to cook the spices. Move the spice mix to the side of the pan.
6) Add the fish pieces to the same pan, side by side. Reduce heat to medium, and allow the fish to cook in its juices for 5 minutes.
7) Spread the cooked spice mix over the fish, add a cup of water. Let the fish cook in the sauce for 5 minutes. Do not over stir as the fish is delicate.
8) Remove from the heat and garnish with chopped coriander leaves.