Preheat oven to 350 degrees F. Spray a 9x13 baking dish with cooking spray.
In a large bowl, mix together the ground beef, minced onion, paprika, garlic powder and salt until well combined.
Spread the beef mixture evenly into the bottom of your baking dish.
Place the baking dish into the preheated oven for 20-25 minutes, or until the beef is cooked through.
Add on 6 slices of cheese. Return the pan to the oven for another 2-3 minutes, or until the cheese is melted.
Cut or slice and open slider rolls. Spread the hamburger sauce over the bottom of the buns.
Using a spatula, remove the large burger patty and place over the bottom buns. *Note: depending on your bun size you may need to trim the patty.
Top with a layer of pickles and shredded lettuce.
Place the bun tops onto the lettuce and brush lightly with the melted butter. Sprinkle with sesame seeds and dried oregano (optional).
Serve immediately with a side of fries or chips.