Boil water in a pot, then add pork belly (skin down), ginger, shallots, spices, and salt. Boil for 5 minutes, flip, and cook 3 more minutes.
Combine the following ingredients: pepper, soy sauce, onion powder, five-spice powder, annatto powder, ginger powder, paprika, salt, and sugar. Mix well.
Set aside a small portion of the marinade and use it as the dipping sauce.
After boiling, drain and pat the pork belly with paper towels to absorb the excess liquid. Score the meat side of the pork (see photo). Rub the marinade on the meat part of the pork on all sides.
Wrap the pork with aluminum foil, except for the skin side. Using the needle meat tenderizer, poke as many holes as you can on the skin’s surface.
Mix vinegar with salt. Brush this mixture well on the skin.
Refrigerate pork for 4 hours to dry the skin (or sun-dry/use a hairdryer). Preheat air fryer to 400°F. Air fry pork at 356°F for 15 minutes, skin side up. This is the first of 3 air frying sessions.
Brush the skin with the vinegar and salt mixture. Next, air fry it for 15 minutes at 375 degrees F.
Remove the aluminum foil and brush the rest of the vinegar mixture on the skin.
Once done, air fry the pork for another 10 minutes at 400 degrees F.
Boil reserved marinade with a little water. Add minced garlic and chili pepper once simmering. Reduce heat and simmer until sauce thickens.
Let the pork rest for about 15 minutes, then cut it into pieces of your preferred size. Serve it with Bánh Mì (Vietnamese baguette), Bánh Hỏi (woven vermicelli), pickles, cucumber, and vegetable salad.