Preheat a cast-iron skillet or griddle over medium-high heat
Lightly butter one side of each tortilla
Take about ¼ cup of ground beef and roll into a loose ball
Place the tortilla butter side down on a flat surface and place a beef ball in the center
Smash the beef directly onto the tortilla using a spatula or burger press to create a thin patty
Season with salt and pepper
Cook for 2-3 minutes until the edges of the beef are crispy and caramelized
Flip the taco so the tortilla side is now on the pan and press down slightly
Immediately place a slice of American cheese on the hot beef patty
Cook for another 1-2 minutes until the tortilla is golden and slightly crisp
Remove from heat and repeat with remaining beef and tortillas
In a small bowl mix all Big Mac sauce ingredients until well combined
Spread a generous amount of Big Mac sauce over the melted cheese on each taco
Top with shredded lettuce diced onions and sliced pickles
Fold slightly and serve warm