In a large mixing bowl, combine the ground beef with onion powder, garlic powder, salt, and black pepper. Using your hands, mix the ingredients gently until just combined; be careful not to overwork the meat to maintain tenderness.
Divide the meat mixture into 12 equal portions, shaping each into small patties. Make sure they are slightly larger than the buns, as they will shrink during cooking.
Preheat your grill or a stovetop skillet over medium-high heat. Carefully place the patties on the hot surface and cook for approximately 3-4 minutes on each side. They should be well-browned and cooked through. In the last minute of cooking, place a quarter slice of American cheese on each patty to melt.
While the patties are cooking, prepare the special sauce by whisking together the mayonnaise, ketchup, yellow mustard, and sweet pickle relish in a small bowl until smooth and well blended.
To assemble the sliders, spread a generous dollop of the special sauce on the bottom half of each slider bun.
Place one cooked beef patty on top of the sauce-drenched bun. Add a handful of shredded lettuce and a few slices of pickles for crunch and flavor.
Top each slider with the upper half of the bun, pressing down gently to secure the ingredients in place.
For an extra layer of flavor and warmth, you can place the assembled sliders back in the skillet for 1-2 minutes, toasting the buns until they turn a lovely golden brown.
Notes
Serve with extra pickles and special sauce for dipping.