Preheat oven to 350 degrees F.
Spray a 9 x 13 inch baking dish with nonstick cooking spray.
Slice rolls horizontally (keeping them connected) and place in the bottom of prepared baking dish; set aside.
In a small mixing bowl, whisk together mayonnaise, French dressing, pickle relish, onion, vinegar, sugar and salt to make the special sauce; set aside.
In a large skillet over medium heat, add ground beef, onion, seasoned salt and pepper.
Cook until onions are translucent and beef is browned. Drain excess grease and set aside.
Spread half of the special sauce on bottom rolls.
Spread half the beef and onion mixture on top.
Top with sliced cheese.
Spread remaining beef and onion mixture on top then spread pickles and lettuce in an even layer on top.
Spread remaining half of special sauce on the inside of the top half of the rolls and place on top of sliders in the pan.
Brush melted butter on top of sliders and sprinkle on sesame seeds.
Cover with foil and bake for 20 minutes.
Cut into individual sliders and serve.