Remove the roast from the refrigerator 2 or 3 hours before cooking.

Preheat oven to 450.

Rub butter on the cut ends of the roast.

Combine flour,salt and pepper together in a small bowl, and then massage the mixture all over the meat.

Set the roast, rib side down, in a shallow roasting pan (the ribs act as a natural rack), and place in the oven. Roast for approximately 20 to 30 minutes, or until the roast is nicely darkened. Reduce oven to 350 and continue to roast, basting every 15 or 20 minutes, until the roast reaches an internal temperature of 125 degrees (for medium) on an instant-read thermometer. 115 to 120°F for medium rare (125 to 130°F after resting), or 125 to 130°F for medium (135 to 140°F after resting)

Remove the roast to a cutting board and let rest for 20 minutes before carving into either huge slabs or off the bone entirely and then thin slices.