Marinate the fish with salt, a few drops of mustard oil and a pinch of turmeric powder, keep aside.
Heat 1 tbsp oil in the pan, shallow fry the fish till light brown. Keep aside on a kitchen absorbent towel.
To the same pan, throw in the kalonji and 2-3 green chilies. Allow them to splutter.
Add the ginger paste, green chili paste, turmeric powder and salt. Cook till oil starts to release from the masala.
Add 1/4 cup of warm water, lower the heat and gently pour in the milk while stirring continuously. Allow to simmer for 3-4 minutes.
Add the fried fish carefully, throw in the fried boris and cook for another 5-6 odd minutes till the gravy thickens a bit.
Finish with the chopped coriander leaves and a generous drizzle of mustard oil. Serve hot.