Divide the ground beef into 10 portions (1.5 ounces or 45 grams each).
Take one portion, sandwich it between two pieces of parchment or wax paper, and firmly press down until the beef is flattened into a patty about 4 inches in diameter.
Repeat with the remaining portions.
Freeze the beef patties for about 1 hour and 45 minutes, or until solid.
Making the Sauce
Mix the sauce ingredients in a small microwave-safe container.
Microwave for 25 seconds, stir again, and refrigerate for at least 1 hour before use to allow the flavors to meld.
Seasoning
Mix the burger seasoning ingredients and transfer them to a shaker for easy application.
Cooking the Big Mac
Heat a cast iron griddle over medium-high heat.
Place two frozen beef patties on the hot griddle and season liberally with the burger seasoning.
Press down on the patties with a spatula until the juices flow.
Swiftly scrape underneath the patties with the spatula, then lift and flip them.
Cook on the other side, then remove from the griddle.
Assembly
Discard the top (crown) half of the regular hamburger bun, keeping only the bottom (heel).
Toast the reserved heel from the regular bun and the bottom half of the sesame seed bun in the residual grease on the griddle over medium-high heat until golden brown. Toast the top half of the sesame bun as well.
Once toasted, add 1 tablespoon of sauce to each heel, followed by half of the measured lettuce (1/8 cup).
Place a slice of American cheese on the bottom half of the sesame seed bun (atop the lettuce).
Add two pickle slices to the extra heel (the middle bun).
Transfer a beef patty to each heel.
Place the middle bun on top of the bottom half of the sesame seed bun and patty.
Add the onions, top your Big Mac with the crown half of the sesame seed bun, and enjoy.
To "Age" the Burger
Grab a 12x18-inch piece of waxed paper.
Center the burger, right side up, on the waxed paper.
Fold the long ends of the paper over the top (it will resemble a tube with the burger in the center).
Fold the two remaining ends underneath. Wrap snugly, but don't squash the Big Mac.
Let it sit for 5-8 minutes to allow the flavors to meld.