Preparation time: 40 min
Cooking time: 30
600 g (1lb 5oz) Indian herring fillets (hilsa or eelish)
with skin, cut into 4 pieces, or 600g boneless halibut, cut into 8
2 tsp turmeric
juice of ½ lime
4-5 medium fresh green chillies
2 ½ tbsp each of brown and black
350ml (12 fl.oz) warm water
1 tsp red chilli powder
2 tbsp fresh grated coconut (optional)
40ml (11/2fl oz) mustard oil
1 banana leaf (or greaseproof paper)
Wash the fish pieces and rub with a mixture of 1 tsp each of salt and turmeric and the lime juice. Roughly chop 2 of the green chillies; slice the remainder lengthwise.
Soak the mustard seeds in 150ml (5fl oz) of the warm water for 20 minutes, then use a mortar and pestle to blend to a fine paste with the chopped chillies, red chilli powder and grated coconut (if using). Add the remaining warm water as required. The consistency needs to be thick for coating. Fold in the mustard oil and add salt to taste.
Cut the banana leaf into 4 x 15cm (6in) squares (or the greaseproof paper into 8 for the halibut). Place the herring fillet on the leaf, coat liberally with the mustard paste, place a slice of green chilli on top and fold the leaf over to make a closed packet. Secure this with string. In the case of halibut, dip the fish in the paste, add the chillies in the same way, coat well and wrap similarly.
Steam the fish for 10 â€“ 12 minutes in a conventional steamer. Or, to create a sensation, bury the fish parcels in freshly cooked, steaming-hot basmati rice for 20 minutes. Then give it 2 minutes in a hot oven to be absolutely sure and serve as is with the rice.
Another way Bengalis cook this fish is by wrapping it in about five layers of leaves and then cooking in a hot frying pan, turning the parcels over a couple of times and allowing the leaf to char as the fish cooks. You will need to cook it for 5-6 minutes before finishing it off in a hot oven for 3 minutes.