To cook a bone-in pork roast, begin by preheating the oven to 425 F. Line the inside of a large baking dish with aluminum baking foil, and place a baking rack inside the dish.
Turn the pork roast so that the fat covered side is facing up, and make a number of small shallow cuts in the roast with a small knife. Rub salt into the cuts. Turn the roast over, and rub salt and pepper over the underside of the roast. Place the roast on top of the rack in the baking dish, and cook for about 30 minutes until the fat on top has begun to bubble and brown.
Remove the roast from the oven, and wrap it in two layers of aluminum foil. Place it back in the oven, and lower the temperature from 425 to 325 degrees. Let the roast cook for an additional four to six hours or until the internal temperature reaches 150 degrees. Remove the roast from the oven; cover it with aluminum foil, and allow it to sit for 15 minutes so that the juices settle. Spoon some of the juices that have collected in the bottom of the baking pan over the roast before carving and serving it.