Into a bowl add Mayonnaise (2/3 cup), Sweet Pickle Relish (2 teaspoon), Ketchup (1 tablespoon), Granulated Sugar (1/2 teaspoon), Salt (1/2 teaspoon) and Distilled White Vinegar (1/2 teaspoon). Mix until combined and set aside.
Into a pan over a low heat at the Onion (1). Gently cook down the onions until soft and caramalized which should take 30-40 minutes.
Shape the Ground Beef (1 pound) into thin round burgers. Season the burgers on both sides with Salt and Pepper (to taste). Cook for 2 minutes on high heat.
Before flipping, spread Yellow Mustard (2 teaspoon) on the patties and then flip. After 1 minute add American Cheese Slice (2 slice) and top with grilled onions.
To assemble add the mayo spread to the bottom Hamburger Bun (2). Layer Pickle Slices (2), Tomato (2 slice), Iceberg Lettuce (to taste) and the 2 beef patties. Place the other bun on top and enjoy!