Preheat the oven to 350 degrees F. In a large skillet or pan on medium heat, add ground beef, half of the diced onion, salt, pepper, garlic powder, and onion powder. Cook until beef is no longer pink and cooked through, about 5-7 minutes. Drain excess grease in a strainer if necessary.
Carefully cut rolls in half lengthwise with a serrated or sharp knife and place the bottom slider buns on a baking sheet lined with parchment paper.
In a small bowl, add all of the Big Mac sauce ingredients together and mix. Spread half of the sauce on the bottom layer of the rolls.
Top with cooked beef, sliced cheese, lettuce, and pickles. Drizzle the remaining sauce on top and place the top half of bread rolls on the sliders.
Brush melted butter on top of the sliders and then top with sesame seeds (optional).
Bake sliders for 10-15 minutes or until the cheese has melted. Let sliders cool for a few minutes and then cut into 12 sliders. Enjoy!