Make the spice paste: in a spice grinder powder the cumin, cardamom, cloves, cinnamon and peppercorns. Put the powder in a food processor with the chilli, garlic, ginger and lemon juice. Process into a paste.
Mix the pork with the spice paste. Cover and marinate 1 1/2 hours.
Heat the oil in a frying pan and add garlic. Saute 1 minute then add onions and cook until golden. Add turmeric, chilli powder, tomato paste, tomatoes and vinegar. Mix well.
Add pork and salt to taste. Cook 10 minutes, stirring. Add water and simmer 30 minutes or until pork is cooked through.
Add pepper and serve hot garnished with coriander leaves.