Mustard-Crusted Boneless Prime Rib Roast With Cream Sauce

• 1 (6-pound) boneless prime rib roast, trimmed, tied
• 4 tablespoons store-bought or
• , divided
• 1 cup sour cream
• 1/4 cup prepared horseradish
• 1 teaspoon freshly ground black pepper
• 1/2 teaspoon kosher salt
• 1/2 cup Dijon mustard, divided
• 1/4 cup (1/2 stick) melted unsalted butter

1. Season roast all over with 2 Tbsp. steak seasoning. Transfer to a wire rack set inside a rimmed baking sheet and let sit at room temperature 1 hour.
2. Preheat oven to 225u0b0F. Roast beef until an instant-read thermometer inserted into the center registers 120u0b0F, 3 1/2-4 hours (start checking every 5-10 minutes after 3 1/2 hours). Tent with foil and let sit at least 30 minutes and up to 1 hour. Increase oven temperature to 500u0b0F.
3. Meanwhile, whisk sour cream, horseradish, pepper, salt, and 1/4 cup mustard in a small bowl; set aside.
4. Remove string from roast; discard. Stir butter and remaining 1/4 cup mustard in another small bowl. Using a pastry brush, thickly coat roast with mustard-butter sauce. Coat with remaining 2 Tbsp. steak seasoning. Roast beef until a brown crust forms, 5-10 minutes. Transfer to a cutting board and carve. Serve with sour cream sauce alongside.
5. Sour cream sauce can be made 1 day ahead. Transfer to an airtight container and chill.

storebought, sour cream, horseradish, freshly ground black pepper, kosher salt, dijon mustard, butter

Taken from www.epicurious.com/recipes/food/views/mustard-crusted-boneless-prime-rib-roast-with-cream-sauce (may not work)