Combine all ingredients in a bowl except the pork. Mix to combine. Reserve half of this mixture and out aside for later.

Add the pork into the remaining sauce and cover completely. Place in the refrigerator and marinate for at least three hours or overnight.

Once marinated, preheat oven to 180C. Take the pork out of the marinade and place on a lined baking tray and grill in the oven for 30 mins on one side using the reserved liquid to baste at least three or four times during cooking. 

Turn the pork belly over and baste again twice while grilling. The pork should have crispy char grilled outer edges on completion but still be melt in the mouth moist and soft meat on the inside. 

Serve scattered with the sliced spring onion.