Cut the aubergine into 1 inch cubes. Peel and finely dice the shallots, ginger, garlic and chilli's. Bruise the lemongrass with the back of a knife., tear the lime leaves into small pieces.
Place all of the remaining dry spices into a frying pan and toast for a few minutes. Pound all of the spices in a pestle and mortar till they are fine.
Peel the potato and cut into 1 inch dice.
Heat the oil in a large pan, when hot add the diced chilli, shallot, garlic, lemongrass and ginger, cook for a minute then add the rest of the spices. Put the diced potato into the oil and cook for 5 minutes, stirring all the time to prevent burning, next add the aubergine and coat in the spiced oil, add the tamarind and the coconut milk, reduce the heat and simmer for 45 minutes or until the potato is tender. Remove the lemongrass before serving.
Wash the coriander well and tear into small pieces. Cut the spring onion into strips and put into cold water. Smash the cashews and toast in a hot pan. When you serve the dish finish it by scattering these over the top.
«This dish is normally served with a pickle of some kind to help cut through the rich coconut milk.»