In a small bowl, combine the secret sauce ingredients. Set aside.
In a large bowl, combine the ground beef, garlic powder, salt, and pepper.
Line a sheet pan with foil, and press the meat mixture into a thin rectangle, slightly larger than the rolls.
Preheat oven to 400 degrees, and bake the beef patty for 10-15 minutes, or until browned. Drain the grease out of the pan.
Cut the sheet of rolls in half. Spread on some of the sauce, the lettuce, and then transfer the beef patty on top. Place the cheese slices on top of the beef, and sprinkle on pickles and onions. Drizzle on some more sauce.
Place the tops of rolls back on, and brush with butter. Sprinkle with sesame seeds.
Bake an additional 3-5 minutes, or until the cheese starts to melt. Cut and serve immediately.
