Follow these steps to create your Mini Big Mac Cheeseburgers effortlessly:

1. Prep the Sauce: In a small bowl, mix mayonnaise, ketchup, mustard, sweet pickle relish, and white vinegar. Stir until smooth and set aside. This will be your special sauce.
2. Season the Meat: In a large mixing bowl, combine ground beef, salt, and pepper. Mix until just combined, being careful not to overwork the meat.
3. Form Patties: Divide the seasoned beef into 12 equal portions and shape them into burger patties, making them slightly larger than the mini buns since they will shrink while cooking.
4. Cook the Patties: Preheat a skillet or griddle over medium heat. Cook the patties for about 3-4 minutes on each side, or until they reach your desired doneness.
5. Add Cheese: Place a slice of cheddar cheese on each patty during the last minute of cooking. Cover the pan to help the cheese melt.
6. Toast the Buns: While the cheese melts, slice the mini buns and toast them lightly in another skillet or under the broiler until golden brown.
7. Assemble the Burgers: Take a toasted bun and spread a bit of special sauce on the bottom. Add the cheeseburger patty, followed by shredded lettuce, diced onions, and sliced pickles. Top with the other half of the bun.
8. Repeat: Continue assembling all 12 mini burgers in the same way.

With these steps, you’ll quickly have a platter full of delicious Mini Big Mac Cheeseburgers that are ready to enjoy!