Preheat your oven to 350°F (175°C).

In a spacious bowl, combine the ground beef with onion powder, salt, and black pepper. Mix until well incorporated.

Shape the mixture into patties, around 2 ounces each.

Heat a skillet over medium-high heat and sear each patty for about 3 minutes per side.

In a baking dish, lay half of the slider buns, place patties on top, layer on cheese, pickles, ketchup, and mustard, and cap with the remaining buns.

Cover with foil and bake for 10 minutes until heated through and cheese is melted.