Unwrap tenderloin and slice almost in half, lengthwise. Place between sheets of plastic wrap and pound to about 1/4 - 3/8 inch thick.
Peel off upper layer of plastic wrap, salt and pepper, then spoon on stuffing (see my recipe), enough to spread out to about 1/2 - 3/4 inch thick.
Roll up tenderloin, jelly roll style, and tie with twine. Sprinkle with salt and pepper, and place on roasting pan. Roast in 350 degree oven until a meat thermometer placed in the center reads 140-150 degrees. Time will depend on size of roast.