Preheat the oven to 425°F.
Combine the oil and all of the seasonings in a small bowl. Rub the seasoning paste uniformly over the meat. Put the roast, bones down, on a rack in a roasting pan and roast for 30 minutes.
Carefully check the roast, turn the oven down to 350°F and continue roasting until an instant-read thermometer inserted near the center of the roast reads 120°F for medium rare, 1 ½ to 2 hours.
After you have reached the desired degree of doneness, remove the roast from the oven and let stand for 20 minutes before carving.
After the roast has rested for 20 minutes, carefully transfer it bone-side down to a large cutting board. Insert a sharp knife between the meat and the rib bones, separating the meat from the ribs in 1 large piece to slice the beef into boneless ½-inch-thick slices — OR leave the roast whole and cut between the rib bones, serving one enormous bone-on prime rib chop per diner.