In a small bowl, whisk together all sauce ingredients until smooth. Chill while you prep the tacos.
Heat an electric griddle to 400℉ and let it get very hot! Otherwise heat a dry cast-iron skillet over high heat until very hot. If using stainless steel, add 1 tbsp oil and swirl to coat.
Divide and gently form cold beef into six 2-1/2-ounce balls.
Press each beef ball onto one side of a tortilla as thin and evenly as possible. Season with salt and pepper. Place the tortilla beef-side down on the hot griddle. Immediately press with a burger press or small pan for 5 seconds to set the crust. Sear for 2 to 3 minutes until edges are deeply browned.
Use a stiff metal spatula to release the beef from the pan (it should release easily if fully cooked). Flip so the tortilla side touches the heat. Quickly top with a slice of cheese and cover with a lid or metal bowl for about 1 minute, until cheese is melted and the tortilla is golden and crisp (watch closely).
Fold gently and transfer to a plate. Top with your favorite toppings and a generous spoonful of sauce. Serve immediately.
To batch cook, place finished tacos on a wire rack in a 200°F oven until ready to serve.
Video
Notes
Note 1: Topping Ideas: My favorites include shredded iceberg lettuce, diced cherry tomatoes, diced white onion, diced dill pickles, thinly sliced avocado, and a sprinkle of toasted sesame seeds.Tips for Success: A super hot pan is key to getting that crispy crust. Don’t skip the preheat. The hotter the surface, the better the browning. Better browning = better flavor.Storage: These are best fresh and don’t store well once assembled. Keep uncooked beef, sauce, and toppings separate. Sauce lasts up to 5 days in the fridge.