Heat half the oil in a heavy-based frying pan and add the pork. Stir-fry for 4–5 minutes until browned, remove with a slotted spoon and set aside.
Add the remaining oil to the pan and add the curry leaves, cumin, coriander, onion, garlic and ginger. Stir-fry for 3–4 minutes, then return the pork to the pan with the curry powder. Stir-fry for 2–3 minutes more.
Stir in the vinegar, cinnamon, star anise, cardamom and coconut milk and measured water. Season and bring to the boil.
Cover tightly and cook in a preheated oven at 150°C (300°F), Gas Mark 2 for 2½ hours or until the pork is tender. Serve with crusty bread or rice.