Preheat your Blackstone griddle to high heat, around 500°F (260°C). Allow it to heat for about 10 minutes.

Divide the 1 lb ground beef into 4 equal portions, forming loose balls.

Place each beef ball onto the hot griddle, spacing them a few inches apart. Press down firmly to smash each ball into a thin patty about ½ inch thick.

Immediately sprinkle the patties generously with salt and freshly cracked pepper.

Cook the smashed patties for 2-3 minutes, until the edges are crispy, and juices start bubbling on the surface.

Gently flip each patty and cook for an additional 2 minutes until done to your liking.

Toast your hamburger buns cut-side down on the griddle for about one minute, or until golden brown.

Assemble your burgers by placing a cooked patty on each bottom bun, layering with lettuce, tomato, pickles, and onion slices. Drizzle with ketchup and mustard, and top with the other half of the bun.