Horseradish-Sour Cream Sauce (adapted from Kenji Lopez-Alt's recipe in The Food Lab):
1 cup creme fraiche or sour cream
1/4 cup prepared horseradish (according to taste)
1/2 tsp. white wine vinegar
2 tsp. Dijon mustard
1/4 tsp. kosher salt
1/4 tsp. coarse ground black pepper
Mix all ingredients together in a bowl or container; cover & refrigerate until ready to use.
FOR THE PRIME RIB:
6-7 lb. bone-in prime rib (3-rib), trimmed, cut from the bone and tied back onto the bone
Coarsely ground black pepper
1. Take the rib roast out of the refrigerator and blot dry with a paper towel. Sprinkle on all sides (especially the fat cap) generously with kosher salt and black pepper. Place on a rack over a plate and refrigerate, uncovered, for at least 24 hours or up to 3-4 days. Remove the prime rib from the frig and let sit at room temperature 1-2 hours before roasting.
2. Preheat oven to 250F.
3. Slice the eye of the meat off the bones, place back onto the bones, then tie securely with kitchen twine. Place the roast, fat side up, on a V-rack in a roasting pan and roast at 250F for 4-5 hours, or until it reaches desired doneness: 125F for rare, 130F for medium-rare, and 140 for medium. DO NOT COOK THIS PIECE OF MEAT TO WELL DONE! It will be tough and simply ruined. In my opinion, prime rib is best served medium, with a nice pink color when you slice into it.
4. When the roast has reached the desired inner temperature, remove it from the oven and tent tightly with foil to keep warm and let it rest for at least 30 minutes to an hour.
5. Crank the oven heat up to 500F (or as high as it will go). Uncover the roast and return it to the oven to brown the outside (6-10 minutes). Remove the roast to a chopping board and let rest for 5 minutes. Remove the twine and the bones, then cut the meat into 1/4" to 1/2" slices. Arrange on a platter and serve with au jus or gravy and your fav sides.
Sprinkle liberally on all sides with salt and pepper.
Place the prime rib on a rack over a plate and refrigerate, uncovered, at least 24 hours or up to 3-4 days.
Slice the eye of the rib off of the bones.
Place the meat back onto the bones and tie securely with kitchen twine.
Place, fat side up, on a v-rack in a roasting pan and roast 4-5 hours at 250F to desired doneness.
Remove from the oven, tent loosely with foil, and let rest 30 minutes to an hour.
Crank the oven up to 500F (or the highest temperature you can get to) and roast the prime rib 6-8 minutes, uncovered, until nicely browned.
Slice and serve (here with the horseradish sauce, oxtail au jus, spinach gratin, and Duchess potatoes).
Pour about 4 tbsp. of the pan drippings into a saute pan over medium heat (you can use the same one you browned the roast in). Sprinkle in 4 tbsp. of flour and stir well to make a roux. Cook the roux for a couple minutes to cook out the raw taste of the flour, then add the beef broth. Stir continuously to make sure there are no lumps, and bring to a boil. Once the gravy has thickened, add the fresh thyme. Taste and adjust seasonings with salt and/or pepper, if needed (chances are you won't because the drippings should already be nicely seasoned from the beef). Turn off heat, cover & keep warm until ready to serve.