Note: Do not make anymore than you can eat in one meal. This does not keep well and does not reheat well.
Heat a large pot with water until boiling. Place your pork belly into the water with skin side down for 1 minute. Flip and boil another 30 seconds. Remove from heat and place into a water bath. This will remove the impurities.
Use a sharp knife, score the skin into 1-inch strips, going only deep enough to break the skin, try not to cut too much into the fat, and definitely not into the meat.
Using a meat tenderizer, a metal skewer, a thick wooden skewer, or an ice pic, poke as many holes as you can in the pork skin, being careful not to go too deep and puncture the meat.
Turn the pork meat side up, and sprinkle 1/2 teaspoon salt evenly over the meat. Then sprinkle ½ teaspoon 5-spice powder and rub it evenly into the meat. Finally, sprinkle 1/4 teaspoon ground white pepper and press it in. Be careful not to let any of the spices get onto the skin.
Rinse hands if you've have spices on it, so it won't get on the skin, then turn the pork back skin side up. Sprinkle about 1/2 teaspoon of salt thoroughly over the skin; I prefer using coarser grain salt like kosher salt for this so it's easier to see that you have salted the skin evenly. Let sit for about 20 mins until you see lots of water drawn up out of the skin. Dab it dry, and brush off any remaining grains of salt.
Place pork into a container and refrigerate, uncovered, for at least 18-24 hours to dry out the skin.
To make the pork belly, preheat oven to 375°F, set the rack in the middle of the oven. Put pork on a rack so heat can circulate around the meat, then set it on top of foil-lined baking sheet and wrap the foil tightly around the meat, yet leaving the skin uncovered (like a boat). This will keep the meat tender.
Roast for 70 to 90 minutes or until internal temp reaches a minimum of 145F. 50 minutes usually gives you juicy pork that is still beautifully pink inside. If you want well-done pork you will have to roast it for at least 60 minutes for this size, for a minimum temp of 160°F.
TIP: You can take the pork to this stage up to 4 hours in advance, let it sit at room temp, and broil the skin about 40 minutes before ready to serve.
To Crisp The Skin: Once the pork is done, remove from the oven and brush the skin lightly with vinegar. Increase oven to 425 degrees F and roast for 20-30 minutes or until the skin has puffy and is crispy.
Remove from oven and enjoy! Call me crazy, but I ate this with truffle mushroom soup in Seoul and it was my favorite meal!