I once worked in a restaurant on the coast that regularly sold four roast rib loins in a day. During the tourist season, we would keep eight loins cooking literally around the clock. We’d take the loins to rare, and since the carving station was set up under a heat lamp next to the grill, where the meat would continue to cook in service, so we rotated sections of meat on and off the carving board.
If someone ordered prime rib well done—and, yes, such people do exist in this world—we’d drop a cut into the well of warm au jus we kept at the grill station until meat was grey and the tip and cap had peeled away from the eye. Smart customers who wanted a slice on the done side ordered an end piece.
Our menu called this beef dish prime rib, but we rarely used USDA Prime beef. We most often used a Choice rather than the much more expensive Prime grade, but rib roast is usually called prime on menus because it is, after all, from one of the eight prime cuts in a whole beef (brisket, shank, rib, loin, round, chuck, flank, and plate). Most of the beef you find in supermarkets is Choice or Prime; check the label.
You can bet a rib roast can be expensive, usually from $12 to as much as $27+ per pound; the average is around $15-20. The price can be much cheaper during the major holidays, around $10 to $15 a pound. Bone-in roasts usually have three to seven ribs and are slightly more expensive. A three-rib roast can feed about seven people; figure 16 ounces of uncooked boneless roast per person.
For an evenly-cooked, rib roast, pat the roast dry, brush with oil, coat with sea salt and minced garlic, and place on a on a rack in a heavy pan. Cover lightly with foil and bring to room temperature. Preheat the oven to 500. Remove cloth, place the roast in the oven, wait a half hour, then turn the heat down to 250. In an hour, begin checking with a thermometer. When you get a reading of 130 in the thickest part of the roast, immediately remove the meat from the oven, and let rest about five minutes a pound before carving and serving. Serve with a ramekin of skimmed pan drippings.