No matter what part of the whole tenderloin your cut comes from, it’s a good idea to tie the meat with kitchen twine before cooking. A tenderloin’s thickness varies quite a bit from end to end, particularly if the cut includes the narrow tail. Cinching the meat at one- or two-inch intervals will give it a uniform shape and thus ensure even cooking. Robert Esposito, a third-generation butcher at the New York City shop Giovanni Esposito & Sons, demonstrated his method of tying, which he does after removing the tough muscle known as the chain, any excess fat, and the layer of connective tissue called silver skin.
All Tied Up: How to Roll and Tie a Beef Tenderloin