Anatomy of a Prime Rib

• Some of the tenderest cuts on a steer come from the long group of muscles that run along its spine. While the animal is alive, they primarily help support the backbone, instead of stretching and flexing. This relatively cushy duty keeps the muscles tender, while more heavily worked muscle groups become stringy and tough. The prime rib incorporates the portion of that muscle group that passes along the rib cage, as well as up to seven of the ribs. The roast includes the chewy meat between the rib bones, the cylindrical central rib-eye muscle, and the equally tender cap muscle that surrounds the rib-eye.

Why It's Fit to Be Tied

• Your butcher's time is valuable, and tying the roast with twine is an extra step that adds to its cost. Yet, there are several possible reasons to take that extra time. For instance, rib roasts are famous for their thick veins of fat. If the meat shop is in a health-conscious area, the butcher might trim out a seam of fat and tie the roast to hold it together. The twine might also be intended to draw the roast into a more cylindrical appearance, rather than its natural flattened shape. The rounder roast cooks more evenly, and slices from a tied roast look like an overgrown version of the popular "lollipop" style of lamb chops.

Do It Yourself

• In fact, trussing the roast with twine makes such good sense you might want to do it yourself if the butcher didn't. That's especially true if you like to cover your roast liberally with a seasoning paste or dry spice mixture. Cut the rib bones away from your roast in a single piece, and season them on both sides with your spices. Next, season the rib-eye separately. Use butcher's twine to tie them back together for roasting, and your beef will have a secret layer of flavor between the bones and the eye. You can emphasize this benefit by searing the rib-eye until well browned before reassembling the roast.

Time to Cut Loose

• Once you've roasted the beef to rich and juicy doneness, the twine becomes a liability. Let the roast rest for several minutes, so its juices don't spill out onto your cutting board; then snip the twine away. Sever the rib bones from the roast, if they don't come off in your hand. Place the now-boneless rib-eye on your cutting board and cut it into generous slices. Cut between the rib bones to separate them; then pile your serving platter with the sliced roast and browned rib bones.