Ingredients
Scale
- 1 bone in prime rib roast, 3 bones, about 7 pounds, chine bone removed, bones cut and tied back on
- 1 tablespoon plus 1 teaspoon kosher salt
- 1/2 cup unsalted butter, softened
- 6 cloves garlic, grated or finely minced
- 2 tablespoons chopped fresh rosemary
- 1 tablespoon fresh thyme leaves
- 2 teaspoons coarsely ground black pepper
- 1 teaspoon Dijon mustard
- 1 yellow onion, quartered
- 2 cups low sodium beef broth, for the au jus
- 1/2 cup sour cream, for the horseradish cream
- 2 tablespoons prepared horseradish, drained
- 1 teaspoon lemon juice
- Pinch of fine sea salt
Instructions
- One to two days ahead, rub the kosher salt over the whole roast. Set it on a rack over a rimmed tray, uncovered, in the refrigerator for 24 to 48 hours.
- On roasting day, heat the oven to 250 degrees F. Mash the softened butter with the garlic, rosemary, thyme, pepper and Dijon mustard. Spread it over the entire surface of the cold roast.
- Scatter the onion quarters in a roasting pan and set the roast on them, bone side down, fat side up. Insert a probe thermometer into the thickest part of the eye, away from bone and fat.
- Roast until the center reads 118 degrees F for medium rare, about 3 to 3 1/2 hours for a 7 pound roast. Start checking at 2 1/2 hours.
- Move the roast to a carving board and tent it loosely with foil. Rest for 30 to 40 minutes.
- While the roast rests, pour the pan drippings through a strainer into a small saucepan. Skim off most of the fat, add the beef broth, and simmer for 5 minutes to make the au jus. Keep it warm.
- Stir the sour cream, horseradish, lemon juice and pinch of salt together and refrigerate the horseradish cream until serving.
- Heat the oven to 500 degrees F. Return the rested roast to the hot oven, uncovered, for 8 to 10 minutes, until the crust is deep golden and sizzling.
- Rest the roast 10 more minutes. Snip the strings, lift off the bone slab in one piece, and slice the roast 1/2 inch thick against the grain. Serve with warm au jus and the horseradish cream.
- Prep Time: 20 minutes
- Cook Time: 3 hours 40 minutes
Nutrition
- Serving Size: 8
- Calories: 690
- Sugar: 0
- Sodium: 640
- Fat: 52
- Saturated Fat: 22
- Unsaturated Fat: 24
- Trans Fat: 1
- Carbohydrates: 1
- Fiber: 0
- Protein: 52
- Cholesterol: 165