First make the special sauce by combining all of the ingredients together in a bowl. Set aside.
Preheat the oven to 350*F and butter a 9 by 13-inch baking dish.
Brown the ground beef, along with the onion, seasoned salt, and black pepper over medium heat. Cook until the onions have softened and the beef is golden. Drain well and set aside.
Keeping the rolls connected, carefully slice them horizontally through the middle using a sharp serrated knife. Place the bottom halves of the rolls in the baking dish.
Layer as follows. Half the special sauce, half the ground beef/onion mixture, the sliced cheese, the remaining ground beef mixture and finally the pickles. Drizzle with the remaining special sauce.
Place the top halves of the rolls on top, cut side down. Brush the tops with melted butter and sprinkle with sesame seeds. Cover tightly with foil.
Bake for 20 minutes in the preheated oven. Cut into individual sliders and serve. Pass the lettuce and raw chopped onion for people to place in their own sliders. Enjoy!