Posto Rui (Rohu fish cooked in poppy seed paste)

I was thinking for long, what should I post for my very first post of the year, when everyone in the blogosphere is posting such yummy cakes. After thinking a lot, I decided to post a bengali recipe which I give more priority for my blogs. In Bengali recipe, I posted very less Non-veg recipes last year, so thought to post a Bengali Fish recipe.
Posto Mach, is a fish preperation, mostly with sweet water fish, Rohu and some small fishes like Parshe or Pabda are cooked with poppy seed paste and a touch of onion, tomato and green chilli. Shellfish like shrimps are also made in this way with poppy seed. There are variations, like some with onions, some without adding onions. Bengalis love for posto/poppy seed knows no boundaries. It's basically a very delicious preperation which goes well with hot white rice.

Ingredients :

Rohu or any sweet water fish : 3-4 pieces
Black cumin seeds/kalonji/kala jeera : 1 tsp.
Onion(sliced) : 1(medium)
Tomato : 1(small)
Green chilli : 1-2(as per your taste)
Poppy seed : 3 tblsp.
Turmeric Powder : 2 tsp. + 1 tsp. to smear on fish pieces
Salt to taste
Oil : 4 tblsp. for fish frying + 2 tblsp. for cooking
Fresh coriander leaves for garnishing(optional)

Method :

• Clean the fish pieces, then rub them with 1 tsp. turmeric powder a 1 tsp. salt. Keep them aside for at least 1/2 an hour.
• Make a paste of poppy seed and green chillies in a dry grinder. Do not grind it into a powder, just grind it coarsely. Take the paste in a bowl and add 2-3 tblsp. water to the paste.
• Take oil in a pan and fry the fish pieces in medium low flame until golden brown from both sides. Keep them aside. (never cook the fish curry in the same oil where you fried the fish, it makes the curry turn black)
• In another pan, take 2 tblsp. oil, season with cumin seeds, when they splutter, add sliced onions. Fry them until lightly brown, add chopped tomatoes.
• When tomatoes get pulpy, add poppy seed paste and turmeric powder. Mix with onions and tomatoes. Stir for a minute or two or until it is little bit brownish. Then add 1 cup of hot water into it. Season with salt. When water start to boil, add fish pieces.
• When water dries up and a medium thick gravy left, remove from heat. Garnish with fresh coriander leaves and serve hot.