Preparation:

Step 1: Make the Special Sauce

1. In a small mixing bowl, combine mayonnaise, ketchup, mustard, chopped pickles, and vinegar.
2. Add a pinch of salt and black pepper, mixing well until smooth.
3. Taste and adjust seasoning as needed. Set the sauce aside for assembling later.

Step 2: Form the Burger Patties

1. Divide the ground beef into 12 equal portions.
2. Shape each portion into a thin patty, slightly larger than the size of your burger buns to account for shrinkage during cooking.
3. Sprinkle both sides of the patties with salt and black pepper.

Step 3: Cook the Patties

1. Heat a large skillet or grill over medium-high heat.
2. Place the patties onto the hot surface and cook for 2-3 minutes per side.
3. Once flipped, immediately add a slice of cheese to each patty to allow it to melt.
4. Stack three cheesy patties for each burger and keep them warm.

Step 4: Prepare the Buns

1. Lightly toast the burger buns on the grill or in a skillet for a golden-brown crust.
2. This step enhances flavor and helps the buns hold the burger’s weight.

Step 5: Assemble the Cheeseburgers

1. Spread a generous layer of the special sauce on the bottom bun.
2. Add a crisp lettuce leaf, followed by a slice of tomato and pickles.
3. Place the stack of three cheesy patties on top of the vegetables.
4. Top with fresh onion slices and an additional dollop of special sauce.
5. Cover with the top bun and secure with a skewer if necessary.