Combine all special sauce ingredients in a small bowl. Refrigerate until ready to use. For best flavor, chill for 2 hours or overnight.
For the Big Macs
Divide the ground beef into 1/3 pound sections. Split each 1/3 in half and roll into a ball. Press each ball between parchment paper to make 6 thin patties total. Season with salt & pepper. Pan fry burger patties in butter until cooked through. Top each burger with a slice of cheese.
You'll need a top, bottom and middle bun for each Big Mac. Lightly toast buns.
Spread a generous amount of special sauce onto each bun. On bottom bun add fine diced onion and shredded lettuce. Top with cheese burger and three pickle slices. Repeat with middle bun, sauce, onion, lettuce, cheese burger, pickles. Finish with top bun.
Delicious served with shoestring fries and a milkshake!
For Gluten Free Sweet Potato 'Buns'
Slice sweet potato into 1/4-inch thick rounds. Brush with olive oil and bake in oven at 425° F for about 25 minutes until golden and tender. Build Big Mac as instructed above using sweet potato in place of buns.