Next, light the earthen fireplace or preheat the gas stove.

Heat the pan and pour in 1 tbsp of mustard oil. When the oil is hot, add the Hilsa fish tail pieces. (Pro Tip: Wait for the oil to smoke lightly, or the skin will stick and tear.)

Fry the Hilsa fish pieces on both sides.

Take out the fried fish and add the four dried red chilies to the same oil.

Now separate the bones from the fried Hilsa fish pieces by smashing them with a spatula and then using your hands to separate them. (Pro Tip: I always use my fingers here because Hilsa hides tiny, sharp bones everywhere.)

Next, take the chopped onions and mix them with a pinch of salt. Then, mash the fried chilies and finally mix everything together with the mashed fish perfectly.

Add 1 tablespoon of mustard oil. (Pro Tip: Drizzle cold mustard oil just before serving, as heat will kill that sharp, nose-tingling taste.)

Ilish Bhorta is ready to serve.