Shorshe Ilish

Ingredients

• 6 steaks of hilsa (ilish), about 700g total, or use mackerel or trout
• 1 tsp turmeric, for the fish
• 1 tsp salt, for the fish
• 3 tbsp yellow mustard seeds
• 1 tbsp black mustard seeds
• 1 tsp salt, for soaking the seeds
• 2 green chillies, for the paste
• 1/2 tsp turmeric, for the paste
• 4 tbsp cold-pressed mustard oil
• 1/2 tsp nigella seeds (kalonji)
• 4 whole green chillies, slit
• 1/2 tsp sugar
• 150ml warm water
• 1/2 tsp salt, for the sauce

Before you cook

• Rub the fish steaks with the turmeric and salt and leave them for 15 minutes.
• Soak both kinds of mustard seeds in 100ml of warm water with a teaspoon of salt for 20 minutes. The salt is what stops the paste turning bitter.
• Slit four green chillies down one side, keeping the stems on.

Steps

1. Drain the soaked mustard seeds and grind them with the two green chillies, the half teaspoon of turmeric and 50ml of fresh water to a smooth, thick paste.
2. Strain the paste through a fine sieve, pressing hard with a spoon, and discard the husks left behind. Skipping this step leaves the sauce gritty.
3. Whisk the warm water and the half teaspoon of salt into the strained mustard paste.
4. Heat the mustard oil in a wide pan over a high heat until it just begins to smoke, then turn the heat down to medium. Heating the oil first takes the raw bite off it.
5. Add the nigella seeds and the whole slit chillies and let them sizzle for 20 seconds.
6. Pour in the mustard paste mixture and add the sugar.
7. Cook the sauce for 3 minutes, stirring, until it thickens slightly and loses its raw smell. Do not let it boil hard, because prolonged boiling makes mustard bitter.
8. Lay the fish steaks into the sauce in a single layer and spoon the sauce over the tops.
9. Cover the pan and cook over a low heat for 8 minutes.
10. Turn each steak over carefully with a fish slice and cook covered for another 4 minutes, until the flesh flakes at the bone.
11. Take the pan off the heat and drizzle over a final tablespoon of raw mustard oil.
12. Rest the dish covered for 5 minutes, then serve with plain steamed rice.