Marinate the fish with salt, 1 tsp turmeric and 1 tbsp of mustard oil. (The mustard oil ensures the fish doesn't splutter naughtily when dipped in hot oil :) ) Heat mustard oil in frying pan and lightly fry the fish (Please don't over-fry as the fish can get stiff). Keep aside.

Reheat the same oil, add the chopped onions, green chillies and a pinch of sugar and fry till the onions are soft.

Add the remaining turmeric powder, red chili powder and salt. Cook on a moderate flame till oil has been released from the masala. Splash a little water if needed, you wouldn't want the masala to burn.

At this stage, throw in the green peas and stir in the posto paste.

Continue cooking for 4-5 mins on a moderate flame. Add 1 cup of warm water, give it a nice stir and bring to a gentle simmer.

Add the fried fish, adjust the salt and cook for a further 5-6 mins till posto gravy thickens.

Finish with chopped coriander and a generous tbsp of mustard oil.

Serve hot with steamed rice.