Trim the pork to remove any tags, residual bone shards and/or excessive fat.
Rub: Rub the piece of pork with mustard, then sprinkle with the pork rub to create an even dark coverage. Let sit while setting the smoker and waiting for it to come to temperature, about 1 hour.
Smoke: Place the pork on a smoker at 120 degrees C, that has a hickory or similar wood for smoke, about 3 large chunks. Smoke for 3 hours.
Wrap: Combine the apple juice, honey and brown sugar, stirring well. Divide the butter up into thin pads.
Prepare two large layers of foil that can wrap the pork. Place the pork on the top sheet of foil, then add the apple juice mixture and butter. Wrap tightly. Then wrap a second time with the second piece of foil.
Return to the smoker and continue to cook for an additional 3 hours. After 3 hours, using a temperature probe check the temperature and resistance of the pork. The meat starts to reach its finished time at about 90 degrees C, however use the feeling of the pork to make the final decision, the softer it is the easier it will pull, the longer it cooks the softer it gets.
Glaze: Combine the BBQ sauce, park rub and apple juice. Unwrap the pork, using a basting brush, coat the pork with the BBQ sauce mixture then return to the smoker for 15 minutes to let the glaze set.
Rest the pork for 30 to 90 minutes before pulling. The remaining sauce can be stirred through the pulled pork.
Cooking in an Oven
Follow the directions as above, except in an oven. When creating the wrapping liquid add a teaspoon of liquid smoke to give it some smokey flavour.