Divide the ground beef into 12 equal portions. I use a kitchen scale to make them uniform, but honestly eyeballing works fine too. Form each portion into a thin patty roughly the size of your slider bun — don't squeeze or you'll end up with hockey pucks.
Season all patties generously with salt and pepper on both sides. This is non-negotiable since the seasoning won't penetrate as deep once they're cooking. Set them on a plate while you get your cooking station ready.
Heat a large skillet or griddle over medium-high heat for about 2 minutes. You want it hot enough that the meat sizzles immediately when it hits the surface. I like my stovetop method because I can fit all 12 patties at once.
Carefully place patties on the hot surface and don't touch them for exactly 2 minutes. Resist the urge to poke or flip early — that's how you lose all those amazing juices. You'll see the edges turn brown and that's your signal to flip.
Flip each patty and cook for another 1 to 2 minutes on the second side. If you're adding cheese, place it on top right now and cover the pan with a lid to melt it fast. The patties should be cooked through without any pink inside.
Butter the slider bun tops and bottoms, then toast them in a separate skillet for about 30 seconds per side. Golden, crispy buns make all the difference in these 4th july sliders beef family — trust me on this.
Assemble your sliders with one beef patty per bun plus melted cheese if using. Add lettuce, tomato, onion, and pickles on top of the patty, then spread the mayo mixture on the top bun.