In a strainer add 2 tbsp of yellow and 2 tbsp black mustard seeds (50:50), wash under running water, and grind with green chillies to a smooth paste by using your food processor. From this mustard paste use 5 tbsp for making Sorshe Ilish. You can use rest (if anything left) of the paste for making mustard-based fish or vegetable curries.

Or else, you can use ready to use mustard powder (Sunrise brand). If cooking with the mustard seeds powder, use 4½ tbsp of it and follow the package instructions for dissolving.

If you’re cooking with ready to use mustard powder then make the green chilli paste separately along with some water in a food processor.

In a bowl add mustard paste, 3 tbsp mustard oil, turmeric powder, salt (as per taste), nigella seeds, green chilli paste (use only if you’re cooking with store bought mustard powder) and ½ cup of water. Mix well.

In a frying pan (non-stick preferably) add the fish pieces along with the mustard paste mixture. Coat the fish pieces well, just flip them and coat. Add some more water if required (I’ve added ¼ cup of water at this stage). Drizzle some mustard oil (2 tbsp) on top. Cover and cook over low heat for 15 minutes.