Pylsa has become the must-have food for travelers in Iceland, and even though it looks similar to a U.S. ballpark hotdog, one bite of this Icelandic hot dog will instantly set it apart. Lamb is often the featured protein of Pylsa, giving it a robust flavor, and it's usually topped with crispy onions, sweet mustard, raw onions, remoulade, and a particular type of ketchup made with apples.