01 -
Divide the ground chuck into 1/3 pound balls without overworking the meat. Refrigerate for 30 minutes to maintain cohesiveness.
02 -
Using a mandoline, slice onions paper-thin. Squeeze to remove excess moisture and refrigerate.
03 -
Cook bacon in a skillet over medium heat until crispy (10-15 minutes). Drain on paper towels, chop finely, and divide into two portions.
04 -
In a bowl, combine mayonnaise, ketchup, mustard, half the chopped bacon, Worcestershire sauce, apple cider vinegar, all-purpose rub, and red pepper flakes. Mix and chill in the refrigerator.
05 -
Preheat a skillet or griddle over medium-high heat. Drizzle with avocado oil and spread it evenly.
06 -
Place chilled meat balls on the hot surface. Top each with onions and smash them into thin 1/4-inch patties using a burger press or spatula.
07 -
Season patties with salt, pepper, and garlic powder. Cook for 3-4 minutes until edges are crispy.
08 -
Spread a thin layer of mustard on the uncooked side of each patty, flip with mustard side down, and top with pepper jack cheese to melt.
09 -
Toast burger buns on the griddle until golden, about 30-60 seconds.
10 -
Spread baconnaise sauce on the bottom bun, top with two patties, add more sauce and reserved bacon, then crown with the top bun.