01 - Heat a grill pan or skillet over medium-high heat until hot.
02 - Combine ground beef with salt, pepper, and garlic powder in a bowl. Gently mix and divide into 8 equal portions. Shape into patties slightly wider than the buns to account for shrinkage.
03 - Place patties on the hot cooking surface. Cook for 2-3 minutes per side until browned and reached desired doneness.
04 - During the final minute of cooking, place a cheese slice on each patty. Cover the pan to melt the cheese completely.
05 - Lightly toast slider buns cut-side down on the grill or in a toaster until golden.
06 - Spread mayonnaise, mustard, and ketchup on bun bottoms. Add cheese-topped patties, 2 pickle slices each, and optional onion and lettuce. Crown with bun tops and serve immediately.