2 tbsp mild-flavoured oil (to make a paste and to fry)
2 onions, sliced
2 tsp black mustard seeds
8 dried curry leaves
3 medium potatoes (about 400gr) cut into wedges
400gr tin chopped tomatoes
300ml fish stock
200ml coconut cream
Small bunch fresh coriander, leaves picked
1-2 tbsp desiccated coconut, toasted in a dry pan
Cooked jasmine rice
Put the coriander and cumin seeds in a small pan (without oil) over a medium heat and toast for a few minutes until fragrant. Transfer to a mini food processor or pestle and mortar and whizz/grind the toasted spices with the chilli flakes, turmeric, tamarind, garlic and ginger, adding just enough oil to a make a paste. Set aside.
Heat the remaining oil in a large frying pan over a medium heat. Add the onions, mustard seeds and curry leaves and fry for 8 minutes or until the onions are golden. Stir in the curry paste and fry for a further 2 minutes.
Add the potatoes, chopped tomatoes, fish stock and coconut cream to the pan and bubble until the potatoes are cooked through and the sauce has thickened slightly. Nestle the fish in the pan, spoon over a little of the sauce and cook for 2-3 minutes or until just cooked. Remove from the heat, scatter with coriander leaves and toasted coconut and serve with rice, with lime wedges for squeezing.