Ingredients for Mustard-Crusted Boneless Prime Rib Roast with Cream Sauce

• 1 (6-pound) boneless prime rib roast, trimmed, tied

• 60ml store-bought or homemade Montreal-style steak seasoning, divided

• 240ml soured cream

• 60ml prepared horseradish

• 1 teaspoon freshly ground black pepper

• 1/2 teaspoons kosher salt

• 120ml Dijon mustard, divided

• 60g (1/2 stick) melted unsalted butter

Season roast all over with 2 tablespoons steak seasoning. Transfer to a wire rack set inside a rimmed baking sheet and let sit at room temperature 1 hour.

Preheat oven to 107°C. Roast beef until an instant-read thermometer inserted into the centre registers 49°C, 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 260°C.

Meanwhile, whisk soured cream, horseradish, pepper, salt, and 60ml mustard in a small bowl; set aside.

Remove string from roast; discard. Stir butter and remaining 60ml mustard in another small bowl. Using a pastry brush, thickly coat roast with mustard-butter sauce. Coat with remaining 2 tablespoons steak seasoning. Roast beef until a brown crust forms, 5-10 minutes. Transfer to a cutting board and carve. Serve with soured cream sauce alongside.

Soured cream sauce can be made 1 day ahead. Transfer to an airtight container and chill.

Disclaimer

While every effort has been made to ensure the information is accurate and up to date, individual needs may vary and dietary requirements can differ based on personal health conditions. Always check food labels and allergen information before preparing or consuming any recipe. If you have specific health concerns, allergies, intolerances, or are following a medically prescribed diet, seek advice from your GP, pharmacist, or a registered dietitian before making significant changes to your diet or lifestyle.