01 -
In a jar or small bowl, stir together all the sauce ingredients until smooth. You can stash it in the fridge for a couple of days if needed.
02 -
Preheat your griddle to medium-high, aiming for it to reach a hot 425°F.
03 -
Roll the beef into 3-ounce balls, slice your onions really thin, and have your cheese, buns, and seasonings at arm's reach.
04 -
Drizzle some oil on the griddle, make four separate onion piles, set a beef ball on each, and season them with salt and pepper.
05 -
Use a burger press to flatten each ball into the onions, pressing firmly for a few seconds. If the press sticks, try putting some parchment paper in between.
06 -
Flip the patties once the surface browns with a little pink left. Quickly toss on the cheese and let it melt for a minute or two.
07 -
Layer two patties on each bun, slather with your sauce, add any toppings you like, and dive in while they're still hot and gooey!