Prepare your Blackstone griddle by preheating it to medium-high heat. Ensure it's well-oiled.
Divide the ground beef into four equal portions (about 4 oz each). Gently form them into loose balls without overworking the meat. Season generously with salt and pepper.
Place a ball of beef onto the hot griddle. Immediately place a piece of parchment paper on top and use a burger press or sturdy spatula to firmly smash the ball into a thin patty, about 1/4 inch thick. Remove the parchment paper. Repeat with the remaining beef balls.
Sear the burgers for about 2-3 minutes per side, until a deep brown crust forms and they are cooked through. For the last minute of cooking, top each patty with a slice of American cheese, allowing it to melt beautifully.
While the burgers are cooking, lightly butter the cut sides of your brioche buns and toast them on a cooler part of the griddle until golden brown.
Assemble your burgers: place a cheesy smash patty on the bottom half of each toasted bun. Add your desired toppings (like diced onions, lettuce, tomato, pickles, and a dollop of special sauce) and finish with the top bun.