1. Preheat oven to 500 degree.
2. On a paper towel, place horseradish, fold the towel, press and take out the liquid. Put it in a mixing bowl, and keep it aside.
3. Take rib roast out of the refrigerator, at least one hour before cooking. Rinse and pat it dry.
4. To the mixing bowl, add rosemary, salt, pepper, and olive. You may also add a teaspoon of garlic. Mix and add a little more oil, until it gets a paste like consistency.
5. Spread horseradish rub evenly on all sides of the roast.
6. Place the roast on a baking tray with fat side up. This will make the fat melt during cooking, adding more flavor to your dish.
7. Place the roast in oven and cook for about 20 minutes.
8. After 20 minutes, reduce the temperature of oven to 200 degree. Start your times for 20 minutes per pound for medium-rare roast. Allow the roast to rest for about 20 minutes.
9. In the meantime, for Au Jus, place a skillet over medium high heat for about minute. Pour oil and add shallots to it. Sauté for about a minute.
10. Stir in beef broth and simmer for about 3 minutes. Strain.
11. Carve roast by removing the rib bones.
12. Serve roast with Au Jus and parsley garnish.
Your perfectly medium-rare cooked roast should have an internal temperature of 130 degree.