Heat the oil in a kadai or heavy bottomed pan.
Add the whole spices (curry leaves, mustard seeds, star anise and cassia) careful as they may splutter if the oil is too hot.
Once the spices are sizzling and mustard seeds popping add the onion and salt. Continue to cook on a gentle heat for 15 minutes or so.
Add the garlic and fry for another couple of minutes.
Add the Kashmiri chilli powder and stir in, continue to fry until the mixture is a nice deep red colour. Add a splash of water if it starts to stick.
Add the curry Masala and continue to fry for a couple minutes. If it starts to stick add a little of the tomato puree/water mix.
Add half of the tomato puree and water mix. Turn the heat up and reduce back down to a thick paste.
Add the rest of the tomato puree/water mix and continue to reduce until you have a nice thick sauce.
Add the pork and the marinade and stir through.
Turn the pan down to the lowest you can. It wants to be barely a simmer.
Cook for around 2.5 hours after which time the sauce should be nice and thick.
Add the rest of the ingredients and cook for another 30 minutes. If the sauce is too thick for your liking just loosen with a little hot water.
Check the seasoning and add more salt if needed.
Serve with rice and Indian bread