1/2 tsp chilli powder
5-6 shallots or 1 small onion, finely chopped
1/2 tsp turmeric
2 garlic cloves, roughly chopped
2 tsp peeled and grated root ginger
1/4 tsp salt
3 tbsp groundnut oil
5-6 curry leaves
1/4 tsp fenugreek seeds
Pinch of brown or black mustard seeds
1/2 tsp tamarind concentrate
500g whole mackerel, scaled and gutted

Place the chilli powder, shallots or onion, half the turmeric, the garlic, ginger and salt in a blend and blitz to a fairly fine paste. Alternatively, use a pestle and mortar. Heat the oil in a large frying pan and add the curry leaves, fenugreek and mustard seeds. When the seeds have popped, add the spicy paste and gently cook over a low heat for 4 minutes. In a small bowl, mix the tamarind with 4tbsp cold water, then add to the pan and stir.

Wash the mackerels and pat dry with kitchen paper. Cut 3-4 diagonal slits on each side of the fish and season with the remaining turmeric. Carefully add the fish to the pan, nose to tail, cover and simmer for 10 minutes on a low heat or until the sauce thickens and the fish is cooked. For extra sauce, stir in 3 tbsp just boiled water and simmer briefly. Serve hot with crusty bread or plain basmati rice.

The mackerel can be baked in an oven in advance at 180C for 10 minutes or cooked on a barbecue and then added to the sauce in the pan.