01 -
Form the ground chuck into 1/3 pound (150g) balls and refrigerate for 30 minutes to firm up.
02 -
Using a mandoline with proper safety guards or gloves, slice the white onions as thinly as possible. Squeeze out excess moisture and refrigerate until needed.
03 -
Cook bacon until crispy, then chop finely and set aside. Reserve half for the Baconnaise sauce and half for burger assembly.
04 -
In a mixing bowl, combine mayonnaise, ketchup, mustard, half of the chopped bacon, Worcestershire sauce, apple cider vinegar, all-purpose rub, and red pepper flakes. Stir until fully incorporated and refrigerate until serving.
05 -
Heat a griddle to medium-high heat. Lightly coat with avocado oil and place burger balls on the griddle, spacing them 2-3 inches apart. Place a layer of sliced onions on top of each ball, then firmly smash down with a burger press until flat. Season generously with salt, pepper, and garlic.
06 -
Cook for 3-4 minutes until the edges are crispy, then spread a thin layer of mustard on top. Flip the patties, add slices of pepper jack cheese, and cook for approximately 3 more minutes until cheese is melted and patties are cooked through.
07 -
Toast burger buns on the griddle until golden brown. Spread Baconnaise sauce on the bottom bun, add two smash burger patties with cheese, sprinkle with remaining bacon bits, add more Baconnaise sauce on top, and finish with the top bun.