Prepare the Big Mac Sauce:
In a small bowl, combine the mayonnaise, mustard, ketchup, pickle relish, white wine vinegar, garlic powder, onion powder, paprika, and salt. Stir until smooth and set aside.

Make the Smash Burger Patties:
Preheat a cast-iron skillet or griddle over medium-high heat. While the pan is heating up, form the ground beef into 4 equal-sized balls (about 4 ounces each). Season them generously with salt and pepper.

Cook the Smash Burgers:
Once the skillet is hot, add the beef balls to the pan, making sure to leave some space between them. Using a spatula or burger press, smash each ball down to create a thin patty. Cook for about 2-3 minutes on the first side until the edges are crispy and brown. Flip the patties and cook for another 1-2 minutes until fully cooked through and golden.

Warm the Taco Shells:
While the burgers are cooking, warm the taco shells by heating them in a dry skillet for about 30 seconds on each side, or you can microwave them for about 10-15 seconds until soft and pliable.

Assemble the Tacos:
Once the patties are cooked, place one on each taco shell. Drizzle a generous amount of Big Mac sauce over the patty.

Top with Classic Big Mac Ingredients:
Layer each taco with shredded lettuce, shredded cheese, chopped onions, and sliced pickles. Add sliced tomatoes if desired. For an extra touch of freshness, sprinkle with chopped cilantro.

Serve and Enjoy:
Serve the Big Mac Smash Burger Tacos immediately while warm and crispy. They pair perfectly with some crispy fries or a side salad.