Mix spices together.
Rub pork butt/shoulder with canola oil.
Top meat generously with the spice mix, creating a thick, pasty layer.
Allow meat to rest for at least 24 hours loosely covered in the refrigerator.
To cook:
Heat grill on high. Flash grill the meat, searing all sides to seal in natural juices. (Alternate method: preheat oven to 500 degrees and roast for 30 minutes, sealing in all natural juices).
Transfer to a roasting pan and cover tightly with alluminum foil. Place pan in a preheated 200 degree oven and slowly roast until the internal temperature reaches of 145 degrees at it's thickest part.
Remove from the oven and allow the pork to rest for at least 10 minutes or refrigerate for later service.