Place a cooking pan on the gas stove and turn it on. Pour oil into it.

Once the oil become hot, reduce the flame, add black cumin, and stir.

Add two green chilies and stir again for a few seconds.

Add turmeric powder and red chili powder (½ tsp of each) to the pan.

Stir for a few seconds and add a cup of water.

Add the mustard paste which is made with mustard seeds, three green chilies, and a little bit of salt. Salt and green chilies overpower the bitter taste of black mustard. Stir for 5 minutes and add more water. Add salt. (Pro Tip: Strain the paste twice through a fine cloth. This is my trick against bitterness).

Once the water starts boiling, gently add the fish to the cooking pan. Let it cook for 10 minutes.

Add more green chilies.

Add two teaspoons of mustard oil for a strong aromatic flavor. (Pro Tip: Never skip the raw mustard oil finish. This is what gives shorshe maach its real punch).

Cover the cooking pan with a lid and let it cook for 5 minutes.

Turn off the gas stove. Pour the fish mustard curry onto a bowl. Serve it alongside steamed rice or shorshe bata diye alu (mustard-infused potatoes).