Sauce: Combine all of the ingredients together in a small bowl and whisk. Keep cool until ready to serve.
Burgers: Preheat the grill to high heat (450° to 550°).
Season the burgers generously on both sides with salt and pepper.
Add the seasoned burgers to a hot grill and cook for 4 to 5 minutes per side or until dark grill marks have formed and the desired internal temperature is achieved.
Finish by adding on each cheese to the burgers.
To Plate: Place the cheese burger on to the bottom bun and layer on the bacon, caramelized or raw onions, mayonnaise sauce and top bun.
Optional Garnish: Lettuce, tomato and pickle.