What is a smash burger?
A smash burger is made by pressing beef onto a hot cooking surface so the patty browns fast and develops crisp edges.
The short answer
Instead of forming a thick patty before cooking, a smash burger starts as beef pressed onto high heat. The pressure creates more contact with the surface, which means more browning and crisp edge texture.
What to look for
Crisp browned edges, not a thick pub-style patty. Melted cheese and fast assembly while the patty is hot. Simple toppings that do not hide the beef texture.