Preheat a cast iron skillet over medium-high heat until hot.

Place the ground beef balls onto the skillet and use a spatula to smash them down into flat patties.

Cook for about 3 minutes until a crust forms, then flip the patties.

Add a slice of cheese on top of each patty and cook for an additional 1-2 minutes until the cheese melts.

Remove the patties from the skillet and let them rest briefly.

Toast the burger buns on the skillet until golden brown.

Layer lettuce, tomato, and pickles on the bottom half of each bun.

Place the cooked patty on top, then add ketchup and mustard to taste.

Top with the other half of the bun and serve immediately.