Wash the pork and place in a pan. Crush the cardamoms and cloves and grind peppercorns, garlic and ginger. Slice the onions and chillies. Prick the pork all over with a fork, then add the cardamoms, cloves, garlic, ginger, vinegar, salt, pepper, cinnamon stick and curry powder and leave to marinate for 1 hour. Cover the pan and cook over a medium heat until the pork is tender. Remove the pork and gravy to a bowl. Heat the oil and stir fry the curry leaves and onion for 2-3 minutes. Place the meat back into the pan together with the gravy and cook for a few minutes Discard the cinnamon stick, then slice the meat and garnish with sliced chillies. From "A taste of Sri Lanka" by Indra Jayasekera, Isbn #962 224 010 0