Step 1: Prepare the Prime Rib Roast

Begin by preparing a 6-pound prime rib roast.

Season it with 30 grams of kosher salt, which is about 1% of the meat’s weight, at least 24 hours in advance to enhance its flavor.

This dry brining process will ensure a well-seasoned roast.

On the day of cooking, preheat your oven to 250°F (120°C) and adjust the oven rack to a low position to accommodate the roast.

Remove the rib bones from the roast and tie them back onto the meat, which will help in even cooking.

Allow the roast to sit at room temperature for 5 to 6 hours before cooking for more even heat distribution during roasting.

Step 2: Brown Bones and Prepare Broth

In a large pot, heat 3 tablespoons of olive oil over medium heat.

Add 3 pounds of meaty bones, such as oxtails or neck bones, to the pot.

Brown them on all sides for approximately 10-12 minutes to develop a rich flavor.

Then, add 5 cloves of garlic, 2 large chopped carrots, 3 chopped ribs of celery, and 1 chopped onion to the pot, stirring to combine.

Stir in 1 tablespoon of tomato paste and cook for an additional 10 minutes to deepen the color and flavor.

Step 3: Deglaze and Simmer the Broth

Pour in 1/2 cup of dry red wine and scrape the bottom of the pot to deglaze any browned bits.

Add 6 cups of low-sodium beef stock and bring the mixture to a boil.

Once boiling, reduce the heat to a simmer and add 2 sprigs of thyme and 1 bay leaf.

Let this mixture simmer uncovered for the duration of the roast’s cooking time to develop a flavorful au jus.

Step 4: Roast the Prime Rib

Insert a meat thermometer into the center of the roast to monitor its internal temperature.

Place the roast in the preheated oven and cook for approximately 3 hours, or until it reaches an internal temperature of 115°F for rare or 120°F for medium-rare.

Once the desired temperature is achieved, remove the roast from the oven and tent it with foil.

Allow it to rest for 20-30 minutes, which will help in redistributing the juices throughout the meat.

Step 5: Prepare Horseradish Sauce

While the roast is resting, prepare the horseradish sauce.

In a bowl, combine 1 cup of sour cream, 5 tablespoons of prepared horseradish, 1 tablespoon of Dijon mustard, 2 teaspoons of Worcestershire sauce, and 2 tablespoons of mayonnaise.

Mix until smooth and set aside to serve with the roast.

Step 6: Finish and Serve the Roast

After resting, place the roast under the broiler for 1-2 minutes on each side to achieve a nice brown crust.

Once finished, remove the roast from the broiler and let it rest for a few minutes before slicing.

Strain the au jus and, if desired, remove excess fat using paper towels or ice cubes.

Slice the roast and serve it with the au jus and horseradish sauce to accompany your perfectly cooked prime rib.