01 -
Mix all sauce ingredients in a bowl or jar. Can be made ahead and stored in the fridge for several days.
02 -
Get your griddle smoking hot at medium-high heat, aiming for 425°F.
03 -
Portion beef into 3-ounce balls, slice onion super thin, and have your cheese, buns, and seasonings ready to go.
04 -
Oil the griddle, make four piles of sliced onion, place a beef ball on each, and season well with salt and pepper.
05 -
Use a burger press to smash each patty into its onion bed, holding for a few seconds. Pro tip: use parchment paper if the press sticks.
06 -
When tops are mostly brown with some pink spots, flip carefully to keep the crispy crust intact. Immediately top with cheese and cook 1-2 minutes more.
07 -
Stack two patties on each bun, add your special sauce and favorite toppings, and serve while hot and melty!