
Prepare the char siu marinade by mixing together the brown sugar, oyster sauce, hoisin sauce, light soy sauce, dark soy sauce, shaoxing, garlic powder, 5 spice, salt, and MSG.
Add the pork butt and coat it evenly with the marinade. Cover and refrigerate for at least 4 hours, or up to 24 hours.
Preheat your oven to 400°F (200°C).
Place the marinated pork on a baking sheet or in a roasting pan. Roast for 30-40 minutes, basting with the marinade every 10 minutes, until the pork is slightly charred and cooked through.
In the last 5 minutes of cooking, brush the pork with the glaze mixture of 3 tablespoons of the marinade and 3 tablespoons of honey.
Remove the pork from the oven and let it rest for 10 minutes before slicing and serving.