Trim pork belly. Burn hair on skin. Tie with straws. Blanch in boiling water to keep the shape. Then put pork belly in an earthen pot lined with bamboo mat.
Sauté green onion and ginger in oil. Add Sauce Mix, some rock sugar, some slab sugar and boil. Pour sauce into earthen pot. Stew pork belly for about 2 hours.
Add the remaining rock sugar and slab sugar. Add Sesaoned Black Vinegar and cook again over low heat for about 1 hour.
Put pork belly on a serving plate. Add thickening to the sauce and heat through. Pour sauce over pork belly.