1 5-bone beef standing rib roast (10–12 lbs.),
chine bone removed and tied back on
2 tbsp. kosher salt
1 1⁄2 tbsp. dry mustard
1 1⁄2 tbsp. chopped fresh rosemary leaves
Coarsely ground black pepper, to taste
1. Season beef with salt, including the rack of bones. Rub mustard all over beef; sprinkle with rosemary and pepper. Set the beef in a 12″ × 14″ roasting pan. Cover loosely with plastic wrap and refrigerate for 2–3 days.
2. Remove beef from refrigerator 3 hours before you are ready to roast it, to allow it to come to room temperature. Arrange rack in lower third of oven and heat to 450°. Roast the beef, rib side up, until it begins to brown and sizzle, 20–25 minutes. Reduce temperature to 325°; continue roasting until a meat thermometer inserted in the thickest part of the meat registers 120° (for medium rare), about 2 hours more. Transfer roast to a carving board and reserve any pan juices. Cover loosely with foil and let rest for 25–30 minutes. Remove and discard chine bone.
Reposted from: http://www.saveur.com/article/Recipes/Prime-Rib