Trim the pork of any excess fat and sinew. Cut into lengths, trying to work along the connective tissue as far as you can so you can remove it, to give you lengths around 1 inch (2.5cm) thick that go with the grain. Then cut into slices around ¼ inch (5mm) thick, cutting across the grain.
Crush or grate the garlic and finely chop the cilantro/coriander stems or root. Grate the palm sugar then measure out, packing gently. Place all the remaining ingredients in a bowl - the garlic, cilantro stems, palm sugar, coconut milk, kecap manis/black soy, light soy sauce, oyster sauce, fish sauce and white pepper. Mix everything so well combined. Add in the chopped pork and stir so all the slices are coated with the mixture. Cover and refrigerate while it marinates - at least 2 hours, but overnight is also good.
If you are using wooden skewers, remember to soak them at least 20 - 30 minutes in water before using to avoid them burning.
When ready to cook, thread the pork onto skewers, threading through the thin side - you can scrunch the slices down a little but thread the pork so it's in line with the other pieces and the flatten it a little so it will lie relatively flat when cooking.
Cook on the grill for a few minutes each side until the edges are going slightly caramelized and the pork is cooked through - exact cooking time will vary depending on thickness of pork and grill heat etc.
Serve with sticky rice, jaew dipping sauce and/or sides of your choice.