Thinly slice pork shoulder and set aside.
In a mortar add in cilantro root, garlic cloves, black peppercorn, and brown sugar. Using a pestle, ground until well combined and a rough paste is formed.
Once paste is formed, stir in the oyster sauce, light soy sauce, dark soy sauce, and coconut milk. Mix until well combined.
Coat sliced pork shoulder cornstarch, mix until all pieces are coated.
Pour marinade over pork shoulder and marinate for 2 hours or over night.
Skew pork slices into bamboo skewer making sure to tightly pack the pork pieces.
Once skewed, refrigerate the skewers for 30 minutes to help the skewers keep its shape.
Grill/grill pan: preheat grill or grill pan over medium-high heat, grease grill with avocado oil. Place skewers on grill and cook for 10-12 minutes flipping over halfway through.
Air Fryer: lightly grease air fryer basket, place skewers in the air fryer, and cook at 375F for 12-14 minutes flipping halfway through.
*It's best to use a fattier cut of pork like pork shoulder, pork butt, pork collar. If using pork chops/loin keep the fat cap on the pork and make sure each skewer has a fatty piece.
**If using a leaner cut of pork, set aside 1/4 cup of the coconut milk to baste the pork skewers each time you flip it. This will help keep the pork moist and juicy.