Grind the mustard with one green chilli and a pinch of turmeric powder into a smooth paste.
Keep aside. Marinate the fish pieces with a pinch of salt and turmeric powder for 10 minutes. Heat oil in a pan & fry the fish till light golden in colour. Drain and keep aside.
Temper the same oil with kalonji and remaining green chilies. Now add the mustard paste, tomato paste, salt and turmeric powder. Stir for a few seconds.
Then add 1/2 - 1 cup water. Bring it to a boil. Gently drop in the fried fish pieces. Cover and simmer for 2-3 minutes on a medium flame.
When done, add the raw mustard oil and switch off the flame. garnish with coriander leaves.
Serve with hot steamed rice.
