Place the Tenderloin in a large roasting pan. Sprinkle about 1/4 cup of beef stock around the roast. I used a disposable, 18×14 pan, the roast will just about fit. ( I am hoping Santa may be bringing me a fancy roasting pan this Christmas!)
Place the roast in the oven, uncovered, for about 45 – 50 minutes. For rare, remove from the oven at 130 degrees. For medium , remove at 135 degrees and for Medium Well, remove at 140 degrees. Just remember….this roast cooks quick!! You do not want to overcook this beautiful piece of beef. Be sure to check it a 45 minutes. You can always pop it back in the oven, but you cannot un-cook it!!