First take mustard seeds, poppy seeds & green chilli in a bowl. Now add a little water to soak them. Let it soak for about an hour. Then strain it and transfer it into a mixing jar, then add some curd & some garlic pods in it. Now add a little water and grind them into a smooth paste. You can even add some salt and turmeric powder too while grinding. I have added them later. You can add them as per your wish.

Now heat a pan; add sufficient amount of mustard oil for frying the pieces of fish. Once they are 70 percent fried, take off the Pomfret pieces from the pan keep them aside. Now in the same pan slightly fry the boiled potatoes too so that it turns a little crisp from outside.

Then add some more oil, when it gets heated, add a tsp of kalounji & some slit green chillies. Then add some sliced onion & tomato in it and fry them well. Add some salt so that the onion slices doesn't gets burnt. Fry them for
3 to 4 minutes.

Then add the mustard and poppy seeds paste in it. Now mix everything well, add little water and fry them for about 2 mins. Donot over fry them or else the mustard paste would turn bitter.

Then add some lukewarm water as required, it shouldn't be complete curry consistency but slightly masala kind-of but the water should be enough to cook the fish completely. After adding water, add some salt and turmeric powder as required. Give it a mix. Now cover the pan until the water comes to a boil.

Once it comes to a boil, gently drop the Pomfret pieces in it. You can even add the boiled potato pieces at the same time or add it after 3 to 4 mins. Now gently mix everything so that the fish doesn't gets break. Now take a small bowl, add 2 tsp of aam-tel (bengali pickle) in it. Smash it well with the back of the spoon along with the mango pieces. Now add it into the curry & give a gentle mix.

Now cover the pan and cook at a low flame for about 8 to 10 mins. Finally add some chopped corriender and sprinkle a tsp of mustard oil and mix it. Now switch off the flame. Your Pomfret er Tok-Jhal is ready to serve. Serve it hot with some steamed rice and believe me it just tastes heaven. Do try it out and do notforget to cooksnap me.