Prime Rib Roast

0 Let the rib roast rest on the counter at room temperature for 1-3 hours before roasting.
1 Preheat the oven to 450°F.
2 Whisk the melted butter, salt, pepper, thyme and lemon zest together. Massage it thoroughly over the entire rib roast.
3 Lay the roast on the center of a rack in a roasting pan, and roast at 450°F for 20 minutes.
4 Reduce the temperature to 325°F and roast for 15 minutes for each pound of uncooked roast (so, a 6-pound roast will need 1½ hours). Note: this timing will end in a medium-rare finish; reduce the equation to 14 minutes for each pound for a rare finish.
6 If you're making the optional creamy horseradish sauce, whisk all ingredients together in a bowl and refrigerate for at least one hour to thicken.
5 Remove the roast from the oven and let it rest, covered loosely with foil, on the counter for 30 minutes before carving. Then carve, serve, and enjoy!