1 (4-bone) prime rib roast (from the loin end), about 9 pounds once trimmed, ribs removed from roast in one cut to create a rib rack, excess fat removed and reserved
4 teaspoons kosher salt
Freshly ground black pepper
4 sprigs rosemary
4 garlic cloves, unpeeled and smashed
1. The night before cooking, liberally season the prime rib with the salt and some pepper. Refrigerate overnight.
2. An hour before cooking, remove the roast from the refrigerator to allow it to come to room temperature and preheat the oven to 400°F.
3. Put the reserved rib rack in a roasting pan bone-side up. Scatter any fat and meat trimmings in the pan around the bones. Roast the bones and trimmings for about 30 minutes, or until the fat starts to render.
4. Remove the pan from the oven, put the rosemary sprigs on top of the bones, and then top with the prime rib, cut-side on the rib rack. (The ribs will act as a roasting rack.) Put the smashed garlic in the bottom of the pan with the trimmings. Baste the beef with the fat drippings and return the pan to the oven.
5. Cook for 30 minutes, then baste the roast again. Reduce the heat to 350°F and cook until the meat is medium-rare, or an internal temperature of 125°F, from 1 hour, 15 minutes to 1 hour 45 minutes, depending on the size of your roast. Keep basting the roast every 30 minutes until it is done. The roast will continue to cook while resting.
6. Remove the roast from the oven and put it on a cutting board to rest, uncovered, for 30 minutes. Slice the prime rib to the desired thickness. Serve with gravy or whole grain or Dijon mustard.