shorshe maach (bengali mustard fish curry)

Serves: 4

Ingredients:
500 grams fish (basa/cod/haddock/ salmon)
1/2 teaspoon nigella seeds
2 green chillies (slit)
1 teaspoon turmeric powder
1/2 teaspoon chilli powder
1 teaspoon brown sugar
salt as per taste
3 tablespoons mustard oil
to make mustard paste:   · ·   ·   ·
1 1/2 tablespoons black mustard seeds
1 tablespoon poppy seeds (optional)
2 tablespoons low fat plain yoghurt
2 tablespoons grated coconut
2 green chillies
1/2 teaspoon salt

Method:
soak the mustard and poppy seeds in 1/4 cup of warm water for 15-20 minutes along with salt. then add the rest of the ingredients listed under mustard paste in a food processor or mixer grinder along with 2 tbsp of water and grind it to a thick, fine paste. keep it aside.
marinate the fish with 1/2 tsp turmeric powder and some salt and keep it aside.
heat oil in a thick-bottomed pan on medium heat. when hot, temper it with nigella seeds and green chillies.
when the seeds crackle, add the ground mustard paste along with turmeric powder, chilli powder, and salt and sauté for 7-8 minutes, stirring constantly.
then add 1 to 1-1/2 cups of water. check the seasoning and add sugar/sweetener and salt if required, and bring it to a boil.
now slowly slide in the marinated fish and cook for 7-8 minutes on medium heat. simmer till the sauce thickens. there should be enough sauce to coat the fish.
serve it hot along with rice.