A smashburger is a method, not simply a thin burger. Loose beef is pressed hard against a very hot flat surface at the beginning of cooking, maximizing contact and crust.
What makes the method work
The surface must be flat, hot and able to hold heat. Cast iron, carbon steel and a heavy griddle work well. Grill grates do not provide enough contact area for the classic crust. The meat should be divided into loose balls rather than tightly rolled spheres.
Smash once, early
Place the beef on the hot surface and press firmly within the first several seconds. Use a stiff spatula and, if needed, a second tool to add pressure. After the crust forms, scraping is more important than pressing. Repeatedly squeezing the patty later pushes out moisture without creating more useful crust.
Single or double?
A double uses two small patties and creates more browned surface relative to meat. A single is easier to eat and usually less rich. Match the total meat weight to the bun: two 2–2.5 oz patties suit many standard buns, while oversized buns can make a normal burger taste bread-heavy.
Control smoke and splatter
Use ventilation, remove loose grease between batches and avoid temperatures so high that fat burns before the beef browns. At home, a slightly lower but stable heat often produces a better second and third batch than an overheated pan.
Best topping strategy
Thin burgers cool quickly. Use toppings that are ready, thinly sliced and easy to bite. American cheese melts rapidly; minced onion, pickles and a thin sauce layer add sharpness without creating a tower.