Preheat oven to 350 degrees.
In a large skillet, over medium-high heat, add the ground beef, break it up within the skillet.
Add the diced onion and fold into the beef.
Season the meat with garlic powder, garlic salt, seasoned salt and black pepper.
Brown the meat, continuing to break up until fine.
Remove the meat from the heat once it's fully cooked and drain any excess fat.
Cut the buns in half and place the bottom half of the buns into a glass baking dish or on a baking sheet.
Line the bottom layer of bread with the cheese slices.
Spread the ground beef mixture evenly over the sliced cheese.
Sprinkle the shredded cheese over the ground beef layer.
Place the top layer of buns over the cheese layer.
Brush the tops of the buns with the melted butter and then immediately sprinkle the tops of the buns with sesame seeds.
Bake uncovered at for 15-20 minutes, or until the cheese is melted and the tops of the buns are golden brown.
Serve and enjoy!