Season pork butt with garlic salt, onion powder and black pepper. Rub well.
In a saucepan mix together mustard, Worcestershire sauce, vinegar, and sugar. Heat just enough to melt the sugar into a syrup consistency.
Take half of the sauce mixture and place in a baking dish or pan that has a cover. - Place pork butt in the pan and cook at 250 degrees F for 4-6 hours.
After four hours, open the oven cover and pour off any liquid (you may reserve this liquid from the pan to use as a sauce on your pulled pork). Re-cover and place back into the oven to finish cooking for 2 more hours.
Remove the pork butt from the oven, place into a cooking pan with both handles. Use your hand to pull apart the meat by pulling down.
Once pulled pour remaining sauce over top of the pork and cook uncovered for 30 minutes at 250 degrees F. - Serve on buns or tortillas. Enjoy!
