i had grown up loving atn st. louis. i grown up loving frozen custard in st. louis. we added that and i wrote out the menu on an envelope literally in six seconds and there it was. >> rose: but it is considered to be, if you're a new yorker, a great burger. what's the essence of a great burger? >> well a great burger has everything to do with what kind of mood you're in because you may sometimes want the kind that's big or the juice is running down your arms. you might sometimes want a little bun. we did a quarter pound burger for shake shack and we ca up with that idea for oneeaso and thatas that we had a sense that there would be lines. we had no idea they would be as long as they are but we didn't want the kind of shack where the doneness made a big difference. once you get beyond four ounces, the people who like rare, medium rare, well, that starts to matter. i happen to like my burgers medium rare. >> rose: me too. >> at four ounces, if there's the right blend of meat in there, it really doesn't matter. so that's how that came about. i think the next question th