There's a joke that I used to hear from friends when I lived in Chicago, who said, "It's not a hot dog, it's a salad!". That sums up the Chicago-style hot dog pretty well. Unlike the classic American hot dog where many people simply put ketchup and mustard on top - Chicago folks go ALL IN! While there are a nearly infinite number of variations, the core ingredients for a "Chicago-Style" hot dog are pretty easy - an all-beef frank topped with tomatoes, sweet pickle relish, chopped onions, pickle spear, pickled sport peppers, and mustard ---- NEVER --- ketchup!