If the tenderloin is not already trimmed and twined, prepare the meat by tucking under any thin ends (so meat is uniform in its depth), and wrap string around the meat about every 2 to 3 inches, knot the string at each end.
Happy holidays! And, happy beef tenderloin to you!!! Oh, is that not how it goes? Then it should be, because this beef tenderloin, with herbed Brussel sprouts and carrots, and horseradish sauce made from Greek yogurt and sour cream, is definitely worth shouting for joy over!