In a bowl, combine the marinade ingredients. Once thoroughly combined, take out 3 tbsp of marinade and put it into a small container. Put the container in the fridge until needed. (This is for the baste)
Prepare the pork by cutting it into manageable sized pieces to fit into your air fryer at 2 cm or ¾ inch thickness. Remove any pork rind and save it for another recipe.
Put the pork and marinade in a zip lock bag and shake until the pork is fully covered. Marinate for 1 - 2 days in the fridge.
When ready, remove the pork from the fridge and let it sit for 30 minutes at room temperature.
Pre-heat the air fryer to 200 C / 400 F.
Combine the baste ingredients together in a small bowl. (Use the 3 tbsp of marinade that you stored in the fridge earlier)
Spray the wire rack or the basket with a little oil and lay the pork on top. Do not let the pork stack on top of each other. You may need to cook the meat in batches. (Note 2)
Baste the pork on both sides with a brush then cook for 6 minutes in the air fryer at 200 C / 400 F.
Take the pork out of the air fryer and baste again on both sides. Cook for another 6 minutes on the side that was previously facing down.
Remove from air fryer. Flip one more time and cook for roughly 2 - 3 minutes or until the pork is cooked and there is a decent amount of char at the edges. You may need to repeat the cooking/flipping/basting a few more times to get to this point, as every air fryer is a bit different.
Repeat with any remaining strips of char siu until all done.