Step 1
Clean the hilsa fish thoroughly and pat it dry. Rub each piece with salt and turmeric. Set aside for 15 minutes.
Step 2
Soak mustard seeds in water for 15 minutes, then grind into a fine paste along with 2 green chilies.
Step 3
Heat mustard oil in a pan until it reaches smoking point, then reduce heat slightly.
Step 4
Add nigella seeds to the oil and let them splutter for a few seconds.
Step 5
Carefully add the mustard-chili paste to the oil and sauté on medium flame for 2–3 minutes.
Step 6
Add a cup of water to the mixture and let it simmer. Add a pinch of salt if needed.
Step 7
Gently place the fish pieces into the pan. Cover and cook for 10–12 minutes on low heat.
Step 8
Turn the fish once midway, making sure not to break the pieces.
Step 9
Once the gravy thickens and oil begins to separate, turn off the heat.
Step 10
Garnish with remaining green chilies and serve hot with steamed rice.
