01 - Preheat a grill or skillet to medium-high heat.
02 - Combine ground beef, salt, black pepper, and garlic powder in a mixing bowl. Gently mix to incorporate, avoiding overworking the meat.
03 - Divide the beef mixture into 8 equal portions and shape each into small patties, slightly larger than the buns as they will shrink during cooking.
04 - Brush the cut sides of slider buns with melted butter and toast them on the grill or skillet, cut side down, until golden brown. Set aside.
05 - Place the patties on the grill or skillet and cook for 2 to 3 minutes per side or until reaching desired doneness.
06 - During the final minute of cooking, add a slice of cheese on each patty and cover to allow the cheese to melt.
07 - Place each cheesy patty on the bottom half of a bun. Add dill pickle slices and red onion if using. Add ketchup and mustard if desired, then cap with the top bun and serve immediately.