To make the spice paste, tip all the ingredients into a blender and process until you have a fine, smooth paste. Add 50ml water, if necessary, to loosen the mixture a little.
Place the pork either in a pressure cooker or in a covered pan with 500ml water and cook for 7–10 minutes in the pressure cooker, or 25–30 minutes in the pan, until the pork is just undercooked, then strain and reserve the meat and stock.
Heat the oil in a pan and sauté the onion until translucent. Add the tomatoes and cook until they soften. Add the spice paste and sauté for 3–5 minutes, then add the cooked pork and cook until it is light brown. Add the reserved stock, vinegar, apples and 200ml water, and season with salt. Simmer over a low heat for 25–30 minutes, until the pork is completely cooked and the gravy has thickened. Garnish with crisp-fried curry leaves, if you wish, and serve hot with rice or bread.