learned this on the food network--amazingly easy.
Put roast on large piece of foil on broiler pan.
Pour melted butter on one side and add rub.
Place under broiler as close as possible for 5 minutes.
Flip roast and repeat butter/rub.
Place under broiler again for 8 minutes.
Then, Seal in foil, leaving room above roast(dome-like) for 1 hour.
In Texas, HEB has an Adam's prime rib rub!
Perfectly medium-rare!