Take your pork out of the refrigerator and let it come to room temperature (about 1 hour).
Heat your oven to 250 degrees.
Season the pork liberally with salt and pepper and set it fat side up on the rack in the roasting pan. Roast pork butt about 40 minutes per pound, or until the internal temperature reads 180 degrees. Remove it from the oven and let the pork rest in the pan under tented foil for at least an hour.
Now, heat your oven to 500 degrees (if your oven has been turned off, give it plenty of time to heat back up, the 500 degrees is important for this step).
Put the pork back into the oven (without foil!) and allow the skin to brown and puff up, cooking15-20 minutes, turning the pan to evenly blister the skin.
Take it out of the oven, tent it with foil and let it rest again about 10 minutes before serving.