Divide ground beef into 8 equal 4-ounce balls, rolling loosely — don't pack tight
Preheat Blackstone to high heat for 10-15 minutes until surface reaches 450-500°F
Add a thin layer of neutral oil to the cooking surface
Place beef ball on griddle and immediately smash flat within 1-2 seconds using a spatula or burger press
Season with salt and pepper immediately after smashing
Cook without touching for 2-3 minutes until edges are crispy and deeply browned
Flip, add a slice of American cheese immediately, cook for 60-90 seconds more
Toast buns face-down on the griddle for 30 seconds until golden brown
Assemble and serve immediately