Though only, we should note from the start, if they are cooked to a proper rare to medium rare. There is simply no point in cooking a Prime Rib Roast if you intend to cook it beyond this point of "doneness".
Previously I blogged about how to do more "inferior" roasts using the Hi-Low heat method. This method is, in my opinion, also the perfect way to cook the royalty of roasts. Follow these instructions exactly to oven cook a Prime Rib roast with two exceptions.
First, a Prime Rib Roast does not need the olive oil. Its delightful fat layering and marbling will take care of the moistening that the olive oil is a substitute for.
If you want to try for something a little different, and truly spectacular, you can do the Prime Rib Roast over charcoal on the BBQ using the indirect method. This always sounds daunting, but is, in fact, rather easy once you get the hang of it (though you should not let family or friends know that!).
This method only really works for roasts that are 3-4 lbs or less, so if you are having a few folks over, you will have to do at least two.
First, after following the instructions for starting up the charcoal grill that I laid out in a previous post, instead of dumping all the charcoal in the centre, you must instead divide the hot coals into two separate piles along the side of the BBQ drum, leaving the centre without coals. This can be done with a cheap accessory fitted side tray for charcoal made by Weber and other companies, or by simply piling it!
After you have the separated coals glowing a red or white hot, take the Prime Rib and put it directly over one of the piles for 5 minutes a side. You want to get grill marks and that lovely searing.
Once you have done this, put the roast in the centre of the grill, with no coals underneath. If it will stand, fine, but usually you are better off to simply rest it one side down and flip it half-way through.
If you do not like the timed method, simply check the roast for "give" as you would a steak.
After done, let the roast sit for only 5 minutes, uncovered, as opposed to the 15 for an oven roast. Again, I suggest slightly thicker slicing.
The BBQ method is incredibly flavorful and worth the effort. The Prime Rib will come out wonderfully juicy and moist, but also with a distinctive smokey charcoal grilled taste that is impossible to acheive any other way. It is truly delicious.