Using a spice grinder, grind the cumin seeds, coriander seeds, peppercorns, cardamom seeds, cloves and cinnamon to a fine powder.
In a food processor, blend the ginger, garlic, chillies and white wine vinegar to a paste.
Mix the ground spice mixture with the paste until well combined and season with a pinch of salt. Rub the mixture all over the pork using your fingers, then set the pork aside, covered, to marinate for 1½-2 hours. (You may skip the marinating if pressed for time)
Heat the oil in a non-stick pan. When the oil is hot, add the onion and fry for 3-4 minutes, or until golden-brown.
Add the marinated pork pieces and fry for 6-7 minutes, turning once, until golden-brown on all sides. Reduce the heat to low, cover the pan with a lid and cook for 50-55 minutes, stirring occasionally, or until the pork is tender. Add small splashes of boiling water to the pan as necessary if the juices in the pan dry out. Add as little water as possible as the resulting sauce should be quite thick.