Firstly, poke some small holes on the pork butt so it can absorb the flavor better and cut into 2 cm wide and 4 cm thick long strips. Set aside and drain.
In a large bowl, mix hoisin sauce, cooking wine, honey, light soy sauce, oyster sauce and Chinese five spice. Combine well.
Add garlic and ginger and pour the Char Siu sauce over the meat or you can use a bag. Turn over for 2-3 times during the marinating process. Keep in fridge for 24 to 48 hours.
Pre-heat oven to 200-degree C (around 400-degree F)
Before baking, add around ½ tablespoon of warm water and ½ tablespoon of char siu sauce with 1 tablespoon of honey. Combine well.
Place the pork on grill and with a layered baking tray. Brush the honey water on both sides.
Place on middle track and back for 10 minutes. And re-brush the honey mixture on both sides again.
Roast again on middle track for another 10 minutes. If you want to hardening the surface, move the grill to up track and roast for another 2 minutes.
Transfer out and brush some sesame oil on surface. Cool down for 3-4 minutes and cut into slices.
Notes
The prepare time do not include refrigerating time.