Preheat grill to medium-high heat.

In a medium bowl, combine ground beef, finely chopped sweet onion, salt, and pepper.

Form the mixture into 4 patties, making a well in the center of each patty.

Cook bacon in a skillet until crisp.

Set bacon aside on a paper towel-lined plate.

Grill burgers for 4 minutes on the first side, then flip and cook for 3 minutes on the second side.

Top each burger with bacon and Swiss cheese.

Cook for an additional minute until the cheese is melted.

Remove burgers from the grill.

To assemble the burgers, slather the bottom side of the pretzel roll with mustard.

Top with the burger and zucchini slaw.

Place the top of the pretzel roll on the burger.

Serve with a side of zucchini slaw.

For the zucchini slaw, in a bowl, combine miracle whip, sugar, salt, apple cider vinegar, yellow mustard, and milk.

Whisk to combine until smooth.

In a separate bowl, combine shredded zucchini, carrot, fennel, raisins, and diced pineapple.

Add the dressing to the vegetable mixture and fold everything together.

Place the slaw in the refrigerator until ready to serve (at least 1 hour).

Enjoy.