Put the tamarind into a small bowl and pour over the boiling water. Set aside until the mixture is cool.

Pour the mixture through a strainer into a bowl, using the back of a wooden spoon to push through as much of the softened tamarind pulp as possible. Pour over a little more water if necessary to make the tamarind juice up to 250 ml (8 fl oz) 1 cup. Discard the contents of the strainer.

Heat 50 ml (2 fl oz) 1/4 cup of the oil in a saucepan. Add the okra and fry until they are golden brown. Transfer to a plate and set aside.

Add the onions, ginger, garlic and chillis to the pan and fry until the onions are golden brown. Add the turmeric and coriander and fry for 3 minutes, stirring constantly. Add a spoonful or two of water if the mixture becomes too dry.

Pour in the tamarind juice, return the okra to the pan and bring to the boil. Reduce the heat to low, cover the pan and simmer for 5 minutes. Stir in the coconut milk and salt, and bring to the boil again. Reduce the heat to low and simmer, uncovered, for 10 minutes.

Meanwhile, heat the remaining oil in a small frying-pan. Add the mustard seeds and curry or bay leaves. Cover the pan and fry until the seeds pop. Stir the contents of this pan into the okra mixture and cook for 1 minute.

Transfer the curry to a warmed serving dish and serve at once.