Season roast liberally with kosher salt, and Kansas City Steak Company Original Steak Seasoning . Roast in a 275 degree oven until the internal temperature reaches 110 degrees for rare, 120 degrees for medium rare, and 130 degrees for medium. Pull it out of the oven, cover with foil, and let it rest for at least 30 minutes, or until the internal temperature stops rising. To make the sauce, combine, horseradish, sour cream, sugar, pepper, and salt. Slice the rested roast, and serve with the horseradish cream sauce.