Preheat your oven to 375 degrees F. Spray a 9x13-inch baking dish with non-stick cooking spray and set aside.
Whisk all sauce ingredients together in a small bowl—Greek yogurt, ketchup, Dijon mustard, dried onion, dill pickle relish, garlic powder, and salt. Set this mixture aside.
In a medium skillet, combine the ground beef, chopped onions, and seasoned salt. Cook over medium heat until the beef is thoroughly cooked and the onions are translucent. Drain any excess fat and set the beef mixture aside.
Slice the Hawaiian Sweet Rolls horizontally, keeping them connected, and place the bottom half in the prepared baking dish.
Spread the prepared sauce onto the bottom half of the rolls. Evenly distribute the cooked beef mixture over the sauce. Layer the cheddar cheese slices and dill pickle slices on top of the beef.
Place the top half of the rolls over the pickles. Brush the tops of the rolls with melted butter and sprinkle with sesame seeds.
Cover the baking dish with foil and bake for 15 minutes. Remove the foil and continue to bake for an additional 5 minutes, or until the cheese is melted and the rolls are slightly golden.