COOK the burgers, resisting the urge to move them, until the edges beneath are brown and crisp, and juices on the surface are bubbling hot, about 2½ minutes. Slide one of the spatulas beneath the burger to release it from the griddle and scrape up the caramelized browned crust. Use the other spatula to steady the burger and keep it from sliding. Flip the burgers. Put the cheese on top and cook the burgers 1 minute longer for medium. Cook more or less depending on your preference.