01 -
Warm up a big cast-iron pan on medium heat. Place your split buns butter-side down into the pan, working in batches if your pan isn't large enough. Let them sizzle for about 1 to 2 minutes until they turn a beautiful golden brown underneath. Move them to a serving dish with the toasted side facing up, then switch off the burner.
02 -
Split your ground beef into 4 equal pieces, roughly 4 ounces per portion. Gently form each piece into a loose ball, then flatten it into a disc about 3 inches across. Sprinkle the salt and pepper generously over both sides. Now pile those super-thin onion slices on top of each patty—don't worry if they seem like too much, that's the whole point!
03 -
Crank your skillet up to high heat and wait until you can feel serious heat radiating from it when you hold your hand above (but not too close!). Drop 2 patties into the pan with the onions facing up, spacing them out evenly. Grab a flat metal spatula and press down hard on each patty, flattening them as much as possible and really pushing those onions into the meat. Let them cook for about 2 to 3 minutes until the bottom gets a nice brown crust and the edges start turning gray.
04 -
Carefully turn each patty over, making sure you scrape up all that delicious crusty bottom and caramelized onions. Lay a slice of American cheese on top of each burger. Cook for another 1 to 2 minutes until the underside gets browned and that cheese melts beautifully. Move these finished burgers onto 2 of your toasted bottom buns. Scrape any stray onions from the pan and pile them on top.
05 -
Cook up the last 2 patties following the same method. Load up your burgers with whatever toppings make you happy, cap them with the top buns, and dig in while they're piping hot.