Prime Rib Roast

Preheat the oven to 350 degrees F.

Scatter the vegetables and halved garlic cloves (2 heads) around the roasting pan and drizzle them with about 2 tablespoons oil. Lay the beef on top of the veggies (to keep the bottom of the roast from burning) in the large roasting pan with the bone side down. (The ribs and veggies act as a natural roasting rack.)

In a small bowl, mash together the 5 cloves of garlic, horseradish, salt, pepper, and olive oil to make a paste. Massage the paste generously over the entire roast. Put the pan in the oven and roast the beef for about 1 1/2 to 2 hours for medium-rare (or approximately 20 minutes per pound). Check the internal temperature of the roast in several places with an instant-read thermometer; it should register 125 degrees F for medium-rare.

Remove the beef to a carving board and let it rest for 20 minutes. The internal temperature of the meat will continue to rise by about 10 degrees.