Step 1: Prepare the pork. Trim any excessive fat from the pork shoulder and cut it into long strips, about 2 inches thick. Pat dry with paper towels. For air frying, cut into 1-1.5 inch thick strips.
Step 2: Make the marinade. In a large bowl, whisk together the 1/4 cup honey, hoisin sauce, soy sauce, Shaoxing wine, brown sugar, five-spice powder, white pepper, minced garlic, red fermented bean curd (if using), and red food coloring (if using).
Step 3: Marinate the pork. Add the pork strips to the marinade, ensuring they are fully coated. Cover the bowl and refrigerate for at least 4 hours, or preferably overnight (up to 24 hours), to allow the flavors to penetrate.
Step 4: Prepare for cooking. Remove the pork from the marinade, letting excess drip off. Reserve 1/4 cup of the marinade for the glaze (this reserved marinade must be boiled separately before use).
Step 5: Oven Method: Preheat your oven to 375°F (190°C). Line a baking sheet with foil and place a wire rack on top. Lightly grease the rack. Place the pork strips on the prepared wire rack. Roast for 20 minutes.
Step 6: Air Fryer Method: Preheat your air fryer to 375°F (190°C) for 5 minutes. Arrange pork in a single layer in the air fryer basket, without overcrowding. Cook in batches if necessary. Air fry for 10-12 minutes, flipping halfway through.
Step 7: Prepare the glaze. In a small saucepan, bring the reserved 1/4 cup marinade and 1 tablespoon honey to a boil. Reduce heat and simmer for 2-3 minutes until slightly thickened. Set aside.
Step 8: Finish Oven Char Siu: After the initial 20 minutes, flip the pork. Brush generously with the prepared glaze. Return to the oven and roast for another 15-20 minutes, flipping and brushing with glaze every 5-7 minutes, until the pork is caramelized and cooked through (internal temperature reaches 145°F/63°C).
Step 9: Finish Air Fryer Char Siu: After the initial 10-12 minutes, brush the pork generously with the prepared glaze. Air fry for another 5-7 minutes, flipping and brushing with glaze every 2-3 minutes, until the pork is caramelized and cooked through (internal temperature reaches 145°F/63°C).
Step 10: Rest and serve. Remove from the oven or air fryer, cover loosely with foil, and let rest for 10 minutes (oven) or 5-7 minutes (air fryer) before slicing against the grain. Serve warm.