For the Big Mac sauce, whisk together all its ingredients in a small bowl and set aside.
On a clean work surface, spread enough meat for 2 burger patties evenly over the flour tortillas. Season each patty with salt and pepper.
Heat a large skillet on MEDIUM-HIGH and add the tortilla meat-side down. Cook for 5 minutes.
Flip the tortilla and add a cheese slice to the patty. Cook for another 2 minutes until the cheese is melted. Repeat with the other tortilla.
Transfer the tortillas to a plate and dress the big mac tacos with the big mac sauce, shredded lettuce, minced onions, and 3 chopped dill pickles. Enjoy!