Preheat the oven to 350 degrees F.

Line a 9x13 baking dish with foil and then spray it lightly with cooking spray. Set aside.

In a large skillet, add ground beef and season with salt and pepper.

Cook the beef until almost done, add the onions and cook for 2-3 minutes or until the onions are soft and translucent.

Drain the beef mixture and set aside.

Using a long serrated knife- slice the rolls in half, lengthwise.

Place the bottom side of the rolls in the prepared pan.

In a small bowl, whisk together the mayonnaise, ketchup, and mustard.

Spread the mixture onto the cut sides of the rolls - both the bottoms in the pan and the insides of the top of the rolls that will be added later.

Sprinkle 1 cup of cheese on top of the bottom rolls in the pan.

Top with the cooked beef mixture.

Add the remaining 1 cup of cheese.

Cut pieces of bacon in half and place one on each roll, optional.

Add a pickle slice to each roll, optional.

Place the top half of the rolls on the top.

Melt the butter in a small microwave-safe bowl or measuring cup.

Stir in the garlic powder.

Brush the tops of the rolls with the butter mixture.

Sprinkle some sesame seeds on the tops of the buns.

Cover with aluminum foil and bake for 20-25 minutes or until the cheese is melted and the beef is heated through.

Remove the foil and continue baking for 4-5 minutes or until rolls are golden brown.

Serve immediately with any side dishes of your choice.

Store any leftovers in the refrigerator.