Grind the mustard to a powder in a mortar and pestle or spice grinder and keep aside.

Whisk the curd well with turmeric powder, salt, half of the ground mustard powder and 1 tbsp of mustard oil.

Add the fish pieces to this marinade, coat well and keep aside for 45 minutes to 1 hour.

Heat the remaining mustard oil in a pan and add the fish pieces along with marinade.

Add the green chillies whole. Since you are adding the whole chillies, it will only impart the flavour and not much heat. But if you prefer more heat, reduce the number of chillies and slit in half. Add a pinch of sugar also.

Also taste to check if the dish has enough of the mustard flavour or add more of the mustard powder.

Cook till the fish is just about done.

Once the fish is cooked, increase heat and break the fish into small pieces with the ladle like you would while making scrambled eggs, though not so vigorously. Basa is a soft fish so it will break easily and the idea is to get small chunks rather than powdered fish.

Stir cook on high till all the extra moisture is absorbed.

Finish off with chopped coriander leaves.