01 -
Divide ground chuck into 1/3 pound balls, gently forming them without overworking. Refrigerate for 30 minutes to ensure they hold together during cooking.
02 -
Slice onions paper-thin using a mandoline and remove excess moisture by squeezing them. Refrigerate until needed.
03 -
In a skillet over medium heat, cook the bacon until extra crispy (10-15 minutes). Drain on paper towels and chop finely. Set aside half for the sauce and half for the burgers.
04 -
Mix mayonnaise, ketchup, mustard, half the crispy bacon, Worcestershire sauce, apple cider vinegar, all-purpose rub, and red pepper flakes in a bowl. Refrigerate to meld flavors.
05 -
Heat a griddle or cast-iron skillet over medium-high heat. Drizzle avocado oil and spread evenly.
06 -
Place chilled meat balls on the hot surface, leaving 2-3 inches between each. Top each with a handful of onions, then smash into 1/4 inch thick patties using a heavy press. Season with salt, black pepper, and garlic powder. Cook for 3-4 minutes until crispy at the edges.
07 -
Spread mustard on the uncooked side of each patty. Flip them mustard-side down, then top each with pepper jack cheese to melt. Cook the second side until done.
08 -
Place split burger buns cut-side down on the griddle and toast until golden brown (30-60 seconds).
09 -
Spread baconnaise sauce on the bottom bun, stack two patties, add more sauce, sprinkle the reserved bacon on top, and crown with the top bun. Serve immediately.