There's only one Shake Shack on Earth that will serve you a breakfast sandwich, and it's at JFK Airport's Terminal 4 (though legend has it the Madison Square Park one used to serve breakfast). This isn't new, but maybe it's new to you? Maybe you were eating a Cinnabon like a sucker on previous airport visits?
As with all fast food breakfast menus, there's a cut-off time, and that cut-off time is 11 a.m. (other Shake Shacks don't even open until 11 a.m.). This morning Do Or Dine's Justin Warner scored the elusive sausage, egg & cheese sammie, noting the "perfect crust on the sausage... gently sweet." He also added that there's cheese and "magic" involved.
— Justin M. Warner (@EatFellowHumans) May 4, 2014
There's also a vegetarian egg & cheese version (300 calories), and a bacon one, which features a "griddled egg topped with all-natural Niman Ranch Applewood smoked bacon and American Cheese" (365 calories, compared to the sausage option's 480 calories). NYC Tastes recommends adding some Shack Sauce, but maybe just add an egg for extra protein.
The JFK Shake Shack is located by Gate B36 in Terminal 4, though another Shake Shack in T4 (Gate B22) is on the way—Eater reports it should be open this or next month, and "presumably" will also have breakfast.
As for rolling breakfast out outside of the airport, one Shack superfan who believes that kind of move would "change the breakfast landscape forever," was recently dealt a hard truth with a side of hope on Facebook: "There's always a chance we'll roll them out to other locations at some point, but no plans at the moment."