1 Remove Roast From The Refrigerator, Loosely Wrapped, 3 Hours Before Cooking. Roasts Should Always Be Brought Close To Room Temperature First, Before They Go In The Oven. Cookbooks Often Call For The Excess Fat To Be Removed. By "Excess" Fat They Mean Any Fat More Than An Inch Thick. The Fat Is What Provides The Flavor And What You Are Paying For With Prime Rib, So You Want To Leave It On. Your Butcher Should Have Removed Any Excess Fat. If Your Butcher Hasn'T Already Done So, Cut The Bones Away From The Roast And Tie Them Back On To The Roast With Kitchen String. This Will Make It Much Easier To Carve The Roast, While Still Allowing You To Stand The Roast On The Rib Bones While Cooking. 2 Preheat Your Oven To 500