Pork loins are among the tenderest cuts from the hog and among the easiest to cook. They're lean but have a protective layer of fat to keep them from drying out, and have an uncomplicated structure that requires no special preparation. The full boneless loin is thicker at the sirloin end and relatively thin and flat at the loin end, but the middle portion -- the center half -- is nicely uniform and makes a roast that cooks evenly.
Trim the thick rind of fat on top of your center-cut roast with a sharp, thin-bladed knife. Leave about 1/4 inch of the fat in place to help keep the roast from drying in your oven.
Season the meat over its entire surface with salt and pepper, or other flavorings as desired. Place the roast on the rack of your roasting pan, and preheat your oven to 350 degrees Fahrenheit.
Slide the roasting pan onto your oven's center rack and roast it, uncovered, for approximately 20 minutes per pound. Center cut loin roasts average 2 to 4 pounds, so this will take 40 to 80 minutes.
Remove your roast from the oven when its internal temperature reaches 145 F when tested with an instant-read thermometer. Alternatively, when the roast reaches 130 F, increase your oven's temperature to 500 F and finish the roast at this high temperature to brown the surfaces and crisp the thin sheath of remaining fat.
Transfer the roast to a serving tray and let it rest, covered loosely with foil, for 10 to 15 minutes before carving and serving it.