Follow these steps to create your amazing Prime Rib with Horseradish Cream:

1. Preheat the Oven: Preheat your oven to 450°F (232°C).
2. Prepare the Rub: In a small bowl, mix the kosher salt, black pepper, garlic powder, onion powder, rosemary, and thyme.
3. Season the Roast: Pat the prime rib roast dry with paper towels. Rub the seasoning mixture all over the roast, ensuring it is evenly coated.
4. Roast the Prime Rib: Place the seasoned roast on a rack in a roasting pan. Roast in the preheated oven for 20 minutes to create a crust.
5. Lower the Temperature: After 20 minutes, reduce the oven temperature to 325°F (163°C). Continue to roast until the internal temperature reaches your desired doneness (about 130°F for medium-rare).
6. Remove and Rest: Once the prime rib reaches the desired temperature, remove it from the oven. Tent it with foil and let it rest for 20-30 minutes to allow the juices to redistribute.
7. Prepare the Horseradish Cream: While the roast is resting, combine the heavy cream, prepared horseradish, and Dijon mustard in a mixing bowl. Whisk until smooth and well combined. Season with salt and pepper to taste.
8. Slice the Roast: After resting, slice the prime rib into thick, even pieces.
9. Serve: Arrange the slices on a serving platter and drizzle with horseradish cream. Garnish with fresh chives if desired.

These steps will guide you to create a stunning Prime Rib with Horseradish Cream that will surely impress your guests!