TIP: The length of cooking time varies by the weight of the pork shoulder, so follow the general rule of cooking 90 minutes per pound of meat.
5 1/2 pounds bone-in pork shoulder
2 tablespoons kosher salt (or about 1 teaspoon per pound of meat)
Preheat the oven to 280°F.
Season the pork on all sides with the salt. Place it in a large cast-iron skillet or a roasting pan with the fat cap-side facing up. If the pork shoulder has the skin intact, score it with a sharp knife down to the lean meat in 2 to 3 places.
Roast for 6 to 8 hours (see Cook's Note) or until tender, checking on it a couple of times during the process. Remove from the oven and allow to rest for 20 minutes before carving.