Preheat oven to 450 degrees F.
Pat the room-temperature standing rib roast (prime rib roast) dry with paper towels or napkins. Smear the cut ends only of the roast with the butter.
Do NOT salt the outside of your prime rib roast, as salt draws out moisture from the meat while cooking. You can use other seasonings, if desired, but I find it is not necessary. I know that some people do salt their prime rib roast before cooking, but trust me and don”t salt – the result will be a juicy, delicious roast to serve your family and guests!
Place the roast, ribs down or fat side up, in a heavy stainless-steel Roasting Pan or other metal roasting pan. Select a roasting pan that has sides at least 3-inches deep. (I do not recommend using nonstick pans, as these pans yield fewer of the cooked-on bits that make the tasty au jus juice or gravy.) The rib bones are a natural rack; you will not need a metal one.
Sear the rib roast (prime rib) for 15 minutes at the higher oven temperature (450 degrees F.), then turn the oven to the lower temperature (325 degrees F.) for the rest of the cooking time. Every 1/2 hour, baste the cut ends of the roast with the fat accumulated in the roasting pan. Do Not Cover the roast.
About 45 minutes before the estimated end of the roasting (bake) time, begin checking the internal temperature (use a good instant-read digital meat thermometer). Play it safe and start checking early, as you don”t want anything to go wrong. This is even more important if you are adjusting for High Altitude Baking.