Insert meat thermometer into thickest portion of meat center. Rub meat with softened butter then sprinkle with steak spices or coarse salt. Place meat fat side up on rack in a shallow roasting pan. Do not add water to the pan or cover. Roast in 450°F oven until the meat thermometer registers 135°F, approximately 30 minutes. The Chateaubriand should be cooked to rare or medium doneness and should not be cooked well done. After cooking, season to taste with Kansas City Steak Company Steak™ Seasoning.