Divide the lean ground beef into 8 equal portions, approximately 2 ounces each, and roll them into loose balls.

Heat a large cast-iron griddle or flat-top skillet over medium-high heat until it reaches a surface temperature of approximately 400°F (200°C).

Place 2 to 3 beef balls on the hot surface, leaving ample space between them.

Immediately place one tortilla directly on top of each beef ball.

Apply firm, even pressure using a heavy-duty burger press or a weighted spatula to smash the beef into a thin, uniform layer that reaches the edges of the tortilla.

Season the tortilla side with a pinch of salt, pepper, and garlic powder.

Allow the beef to sear undisturbed for 2-3 minutes until a deep brown crust (Maillard reaction) has formed.

Using a thin metal spatula, scrape under the beef to ensure the crust remains attached and flip the taco so the tortilla side is down.

Place a half-slice of cheese onto the beef and cook for an additional 60 seconds until the cheese is melted and the tortilla is toasted.

Remove from the heat and garnish immediately with shredded lettuce, onions, pickles, and mustard.