The Daily Meal’s executive editor, Arthur Bovino, says it best when it comes to Shake Shack’s popular sauce:
"Besides the great seasoning and taste of the burger patty, the obvious thing that makes Shake Shack’s ShackBurgers so great is the tangy Shack sauce. It doesn’t have the noticeable bits of relish that you see in In-N-Out sauce, and it’s much lighter in color, but it doesn’t skimp on flavor. Tangy, sweet, with a little zest — when it all comes together with the other flavors, there’s almost a creamy element that rounds out the salt of the burger and the sweet of the bun. It’s a thing of beauty. The day I learned that you could ask for Shack sauce on the side for extra slather on the burger, or for dipping fries was a dangerous one."
As he mentions, Shake Shack’s sauce is very pale in color, which is why we think there’s probably no ketchup in it, and it gets its pale pink shade from seasonings and red-wine vinegar. Yellow mustard adds a bit of tang, and we’ve also included a bit of sugar to balance out the vinegar.
In a food processor fitted with a sharp blade, combine all of the ingredients and process until smooth.
Season with salt and pepper to taste.