the "prime rib" is called "rib roast" when bought as a cut of meat and costs about $10/pound
4.7 pounds (including fat, bone) yielded 6 servings plus soup
6 hours prior to eating: set roast out (so that it reaches room temperature)
5 hours prior to eating: place roast in oven at 375F, uncovered
4 hours prior to eating: turn off oven, let roast stand in oven
1 hour prior to eating: turn oven back on to 375F
15 minutes prior to eating: turn off oven, remove roast from oven, and let roast stand at room temperature
0 minutes: cut the roast to serve for eating
Note 1: If you try to cut the roast when it is really hot, it will just turn into shreds.
Note 2: the roast is never covered. It can make a mess in the oven.