Perfect Christmas Prime Rib with Au Jus

Prep the Roast (Day Before Cooking):

1. • Unwrap the prime rib roast and pat it dry with paper towels.
   • Place it on a baking sheet and refrigerate uncovered overnight. This helps to dry out the surface for a better crust.

Prepare for Roasting:

1. • Take the roast out of the fridge about 1 hour before cooking to bring it to room temperature.
   • Preheat your oven to 450°F (230°C).
   • In a small bowl, mix together the kosher salt, black pepper, thyme, and garlic powder.
   • Rub the roast all over with the horseradish and Dijon mustard, then sprinkle generously with the spice mixture.

Roast the Prime Rib:

1. • Scatter the celery, carrot, and onion pieces in the bottom of a roasting pan. Place the roast on top, fat-side up.
   • Roast in the oven for 30 minutes to develop a golden crust.
   • Lower the oven temperature to 350°F (175°C) and continue roasting until the internal temperature reaches 130°F (54°C) for medium-rare (use an instant-read thermometer). This takes about 15 minutes per pound, but monitor closely.
   • Remove the roast from the oven, tent it loosely with aluminum foil, and let it rest for 30 minutes. The temperature will rise another 10 degrees as it rests.
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Make the Au Jus Sauce:

1. • While the roast rests, skim any excess fat from the pan drippings. Place the roasting pan on a burner over medium heat.
   • Stir in the beef base and 1 ½ cups of water, scraping up the flavorful browned bits from the bottom of the pan. Bring to a boil.
   • Strain out and discard the vegetables.
   • In a small bowl, whisk together the cornstarch and 1 teaspoon of water. Slowly add this mixture to the pan, whisking until the sauce thickens slightly
   • Pour the au jus into a gravy boat or serving bowl.