• Preheat the oven to 375 degrees F and grease a 9x13 baking dish.
• Cook the ground beef and drain the grease. Set aside.
• In the same skillet used to cook the beef, combine the milk, onion powder, mustard, and pickle juice. Bring to a low boil over medium-high heat, stirring frequently. When the mixture begins to boil remove from heat and stir in the shredded cheddar cheese until melted. Season to taste with salt and pepper.
• Add the ground beef and cooked bacon pieces back into the skillet with the cheese sauce. Stir to combine, then transfer to the prepared baking dish. Spread into an even layer and then top with the American cheese slices.

For the traditional crust:

• Pour the warm water into the bottom of a mixing bowl. Sprinkle the yeast over the water and allow it to dissolve (this should just take a minute or two. Add the sugar, salt, and melted butter.
• Add 1 cup of all purpose flour and mix it into the liquid. This is a great time to use an electric mixer with a dough hook if you have one. Continue kneading in additional flour by the ¼ cup or less until the dough is not very sticky and begins to easily form a nice smooth ball.
• Allow the dough to rest for about 5 minutes, then use your hands to form the dough into a 9x13" rectangle. place the formed dough on top of the meat and cheese mixture. I usually find it easiest to form the dough on a lightly floured counter then transfer it to the casserole.
• Whisk the egg in a small bowl, then brush the beaten egg on top of the unbaked dough. Sprinkle with the sesame seeds.
• Bake in the preheated oven for 20 minutes or until the dough is baked through and browned.

For the keto/gluten-free crust:

• In a microwave-safe bowl, combine the butter, mozzarella cheese, and cream cheese. Microwave for 30-second increments until the cheeses are completely melted and combine easily.
• Add the almond flour, baking powder, and egg and mix until uniform.
• Spread this mixture on top of the hamburger in the prepared dish. It helps to use wet hands or a greased spatula when working with this dough. Sprinkle with the sesame seeds.
• Bake in preheated oven for 30 minutes or until the top is golden brown.
• Serve topped with your favorite burger toppings and enjoy!