Prime Rib with Horseradish Cream

Combine first 5 ingredients; rub on all surfaces of roast. Place roast on a rack in a roasting pan.

Bake, uncovered, at 450° for 20 minutes. Reduce heat to 300°, and bake 2 hours and 15 minutes or until a meat thermometer inserted in thickest portion registers 145° (medium rare) or 160° (medium). Let stand 10 minutes before slicing. Transfer roast to a serving platter, reserving 1/4 cup drippings for Blue Cheese Yorkshire Puddings; keep warm. Serve with Horseradish Cream. Garnish, if desired.