1. Bring adequate water to a boil. Add in pork belly and cook over low heat for about 15 minutes (the water must not be over boiled). Remove and set aside to cool. Pierce the skin all over using a pork skin tenderizer. Rub off the oil.
2. Rub the skin with vinegar, turn it over and make 4 crosscuts on the meat. Rub evenly with 1½ tbsp of Marinade A.
3. Turn it over again and scrape off the vinegar from the skin with the blade of knife. Rub evenly with salt and marinate for a while.
4. Preheat oven at 250°C, place pork belly in the oven and bake for 40-45 minutes until the skin turns golden brown and starts to bubble.