PatsFans.com Retired Jersey Club
I've kind of become converted to the basic smashburger technique.
1) Loose ball of quality meat ~85% lean
2) Drop it in the middle of hot cast iron
3) Immediately give it 1 (and only 1!) good smash with a heavy spatula (or whatever) so you get full contact for an even brown crust all across the surface
4) Flip when juices are seeping through the top
Just salt & pepper for seasoning. Favorite cheese is probably a medium cheddar, full extra aged/super sharp is a bit much.
I used to use that technique, but I found it failed to keep the burger from becoming too rounded. So I now go with forming the patty and then making the indent on the top.