In a large bowl, mix together ground beef, Worchestershire sauce, garlic powder, onion powder, salt, and pepper. Press mixture into a 9 x 13 baking dish or quarter sheet pan sprayed lightly with cooking spray. Bake until the patty is medium, about 15-20 minutes.
Slice the entire pack of buns in half lengthwise. Place bottom half into a 9 x 13 baking dish. Spread yellow mustard evently accross the buns. Use two large spatulas to transfer the meat patty on top of the buns. Lay pickles on top of the meat, dividing amongst the sliders. Top with a layer of cheddar cheese slices. At the bun tops, pressing down on them gently.
In a small bowl, combine the melted butter, sesame seeds, and garlic powder. Use a pastry brush to spread the mixture on top of the buns.
Bake sliders for 15-20 minutes, until cheese is melted and tops are golden. Slice sliders into 12 individual portions using a serrated knife. Serve immediately.
Notes
This is a recipe that is best served immediately. To make ahead, prep the ingredients. Bake the meat patty and sliders before serving.