It's no secret that, for the most part, when you see "secret sauce" on a fast food restaurant menu, it's Thousand Island salad dressing. It must have been a curiosity when the concept was first approached, but this peachy-hued condiment actually makes total sense on hamburgers, considering it's made with lots of things that work well on burgers anyway, including mayonnaise, ketchup, mustard, and pickle relish. But Thousand Island on burgers may have never been a thing if the salad dressing hadn't first been put on Reuben sandwiches.
Despite the ongoing debate on who really invented the Reuben (people tend to believe it was either Arnold Reuben in New York City or Reuben Kulakofsky in Omaha, Nebraska), the original sandwich contained corned beef, Swiss cheese, sauerkraut, and Russian dressing on rye bread. The only is that the former contains horseradish for a spicy kick. The addition of a tangy, creamy condiment on a meat-filled sandwich proved to be genius.
So why not put it on other meat-filled sandwiches, like burgers? Fast food purveyors certainly saw the appeal, and today, the condiment is considered a staple at many burger restaurants. Who uses Thousand Island dressing? When McDonald's debuted its Big Mac sandwich in 1968, the company made a brilliant marketing move by advertising the sauce that topped the burger as "special sauce." It created intrigue that translated to sales.
Of course, it was later discovered that the was inspired by Thousand Island dressing, albeit .
