Place rack in center of oven. Heat oven to 500 degrees. With the point of a paring knife, make 1/2-inch slits toward the center all around the roast. Insert the garlic in the slits, accompanied by a needle of rosemary, if using. Rub roast generously with salt and pepper. Place roast and bones, if available, in a roasting pan just large enough to hold them. Roast for 45 to 50 minutes, or until meat reaches an internal temperature of 140 degrees. The meat might still be slightly pink, but this is fine. Don't overcook the roast, or it will be dry and unappealing. Remove roast and bones to a platter. Let meat rest before slicing across. Snip off strings. Juices will collect better in a platter than on a cutting board.