It’s a traditional Bengali preparation. Ilish Machh (Hilsa,Tenualosa ilisa; to know more about Ilish, click here) is cooked with Doi (Dahi/curd) and other spices. Conventionally it is prepared in Mustard oil.
Difficulty level- easy
Marinating time- 10 minutes
Cooking time- 15 minutes
Total time- 25 minutes
Ilish machh (Hilsa fish) - 500 grams
Doi- 200 grams
Mustard oil- 150 grams
Ginger paste- 1 tsp
Turmeric powder- 2 tsp
Mustard seeds- ½ tsp
Green chilli- 8 pieces
Salt- to taste
Wash the Ilish fish pieces. Mix turmeric powder and salt thoroughly and keep it aside for 10 minutes.
Grind the mustard seeds with a pinch of salt and a green chilli with some water to make a thick paste. Heat oil in a frying pan for 2 minutes. Add rest of the green chillies in it after slicing vertically. Then add the ginger paste to the oil and stir fry for 2 minutes. Make a thick paste of the turmeric powder with little amount of warm water. Then add to the pan while stirring continuously. Add 250 ml of warm water and salt to taste. When the curry will start to boil, add the Ilish fish pieces in it. Prepare a mixture of the doi (dahi/curd), ½ tsp turmeric powder and mustard paste. Add this mixture to the pan when the fish pieces become tender. Be careful that the mixture should be added evenly.
When the curry starts boiling again, remove it from the flame.
Add 2 tsp mustard oil and 3 uncut green chillies and cover the pan with a lid.
Traditionally this preparation is done with the raw Ilish fish pieces. But if you don’t like the smell, fry the pieces lightly in low heat.
The mustard seeds should be finely grinded along with the green chillies and salt to avoid bitterness.