Cut the pork into 4 cm cubes. At the same time accurately remove fat and gristle. Put the meat in a suitable bowl, pour vinegar and add salt. Mix well and put in the refrigerator for 2 hours to marinate.
In the meantime, grind the cumin, coriander, cardamom seeds (without shells), peppercorns, cloves and turmeric into a fine powder. Stir through with a tiny bit of the marinade vinegar to form a thick paste. Remove the meat from the marinade and transfer to a clean baking dish. Keep the marinade. Add the spice paste to the meat and mix. Cover the baking dish and refrigerate for one night.
Heat the ghee in a heavy frying pan. Add the onions, garlic and ginger and roast over a low heat for 4-5 mins until soft. Add bay leaves and chili spice and stir thoroughly. Add the meat and stir-fry on all sides, stirring throughout. Increase the temperature and add the marinade. Place a lid on the skillet, set to low temperature and saute for 1 1/2 hours (or until the meat is really tender). Sprinkle garam masala over the dish before serving. Serve hot or possibly cooled to table.
Tip: You can use butter instead of clarified butter in most cases.