A French dip sandwich, also known as a beef dip, is a hot sandwich consisting of thinly sliced roast beef (or, sometimes, other meats) on a "French roll" or baguette. It is usually served plain but a popular variation is to top with Swiss cheese, onions, and a dipping container of beef broth produced from the cooking process (termed au jus, "with juice"). Beef stock, a light beef gravy, or beef consommé is sometimes substituted. The sandwich is an American invention, with the name seeming to refer to the style of bread, rather than any French origin. Although the sandwich is most commonly served with a cup of jus or broth on the side of the plate, into which the sandwich is dipped as it is eaten, this is not how the sandwich was served when it was originally developed. (Full article...)