Butter the potato buns generously on both cut sides and set them aside on a sheet pan or cutting board. While the buns are ready to toast, measure out the pizza sauce into a small bowl and have the pepperoni, mozzarella cheese, and pepperoncini within arm's reach of your cooking station. This prep work takes just a minute and ensures everything is ready when your burgers finish cooking.

Divide the ground beef into four equal portions of about 4 ounces each and gently form them into tight balls using your hands. Don't overwork the meat—handle it just enough to hold its shape. Season all sides of each ball generously with kosher salt and freshly cracked black pepper. I recommend seasoning both the outside and inside by cracking the balls open slightly, as this ensures even flavor distribution throughout the patty.

Heat a cast iron skillet or griddle over high heat until it's smoking hot. Place the seasoned beef balls directly onto the hot surface and let them sear undisturbed for exactly 1 minute to develop a flavorful crust. Using a sturdy spatula, firmly press each ball flat into a thin patty, applying steady downward pressure for a few seconds. The key to a smash burger is creating maximum surface contact with the hot pan, which gives you crispy, caramelized edges. Immediately season the top side of each flattened patty with a pinch more salt and pepper, then cook for another minute until the bottom is deeply browned and slightly charred.

Flip each patty carefully and immediately begin layering the toppings. Place 3 slices of pepperoni on each patty, then distribute 2 tablespoons of the mozzarella cheese evenly over the pepperoni. Spoon about 2-3 tablespoons of pizza sauce over the cheese, and top with 2 pepperoncini slices per burger. Sprinkle a tiny pinch of dried oregano over each patty. The residual heat from the pan will melt the cheese while you finish cooking, creating a cohesive pizza-flavored topping. Cook for just 30-45 seconds more until the cheese begins to melt and the toppings warm through.

While the final toppings are melting, place the buttered buns cut-side down on the hot skillet or griddle for 30-45 seconds until they're lightly golden and crispy. Watch them carefully to prevent burning. Carefully transfer each topped burger patty from Step 4 onto the bottom half of a toasted bun, then crown it with the top bun. I find that letting the burger sit on the bottom bun for just 10 seconds helps the heat soften the bread slightly and lets everything set together nicely.

Transfer the assembled pizza smash burgers to serving plates or a platter immediately while everything is still hot. The melted cheese, warm sauce, and crispy edges are at their peak right now, so serve without delay.