Clean, cut, and take out the head of the fish. Clean inside of the fish and wash thoroughly. Cut the fish into half-inch thick slices

Pat dry with kitchen towel and apply salt and turmeric powder

Wash and cut potatoes into half inch pieces

Wash and slit the green chillies

Dry roast coriander and cumin seeds briefly, cool and grind into fine paste

Heat up 2 tbsp mustard oil to the point it just reaches smoking point

Remove, cool and heat up the oil again on medium heat

Mix in the fish slices few at a time and fry for a minute on each side

Remove and keep aside

Mix in potatoes pieces to the pot and stir fry for 2/3 minutes

Heat up remaining oil in the same pan, mix in kalonji, split chillies, and stir fry

Mix in coriander-cumin paste and stir fry on low heat up fro a minute sprinkling water as required

Mix in 2 cups of water, sautéed potatoes, salt and simmer (boil slowly at low temperature) for 4/5 minutes or until the potatoes are cooked

Gently slide in the pot fried fish slices and simmer