Grind together the soaked red chillies, peppercorns, star anise, cassia bark, cloves, cumin seeds, chopped ginger,chopped garlic, tamarind and vinegar to a smooth paste, adding a little water if required.
Heat oil in a large sauce pan, add onions and sauté until well browned.
Add 100 ml water and let the mixture simmer for 3-4 minutes, stir well.
Add tomato paste, red chilli powder, jaggery, the spice paste and salt, mix well and cook for a couple of minutes.
Add a litre of water, bring to a boil, remove from heat and set aside.
In a thick bottomed saucepan, heat oil and sear the pork belly, ensuring all sides are a nice golden brown.
Pour in the sauce and braise over medium heat for 45 minutes.
Remove the pork belly, place on a chopping board and cut into one-inch strips.
Place back into the pot and cook on low heat for a further 30 min or until the pork is tender.