1. Trim the excess fat from the Prime Rib, but don't remove all of it.
2. Rub the Prime Rib with the oil, so when you apply the steak seasoning it will stick and form a crust.
3. Put the Prime Rib in a roasting pan, and if you have an underliner, utilize it under the meat.
4. Cook in a preheated oven at 375 F.
I won't give you a cooking time for the different levels of doneness, because it is very relative. Not every oven cooks the same way. I do not agree with the "experts" who give cooking time for Prime Rib according to some formula "pounds x minutes".
5. The best way to know when the Prime Rib is ready is to use food thermometer.
6. For medium rare remove it from the oven when the internal temperature reaches 120 F, for medium 125 F, and for medium well 135 F.
7. Let the Prime Rib sit out of the oven for at least 10-15 minutes before cutting, as it continues cooking in the inside.
8. Make sure your thermometer readings are correct by placing it in iced water and calibrating it to read 32 F.
Beef Dripping and wine sauce:
9. Collect the juices from the Prime Rib and transfer them in a pan.
10. Try to remove as much fat as possible.
11. Deglaze the bottom of the roasting pan with the red wine and add it to the meat juices.
12. Bring to a boil and reduce, or use corn starch to thicken the sauce. If you thicken the sause with starch, you need to mix the starch with water first, before adding it to the sauce.
13. Add diced portabello if desired.