For best results, purchase a 3-rib roast or larger. Use an accurate instant-read thermometer and start taking temperatures half an hour before the end of the estimated roast time.
3-rib roast or larger
2 Tbsp salted butter, softened to room temperature

Preheat oven to 450° F. Rinse roast and pat dry; rub cut ends of roast with butter. Place roast into a heavy roasting pan with the ribs down and the fat side up.
Place the roast into preheated oven; after 15 minutes, lower heat to 325° F. Baste roast with drippings in bottom of pan every 30 minutes.

Cook until rib roast reaches an internal temperature of 120-125 degrees F for rare doneness. Remove from oven and place on heat resistant serving tray, cover with aluminum foil, and let sit approximately 15 to 20 minutes. See chart below for recommended temperatures for other levels of doneness.

Note: When inserting the instant-read thermometer, make sure it is in the thickest part of the meat and not resting next to a bone.