There's no need to plop foie gras and shaved truffles onto some ground beef, or gently heat it in a CVap oven and spike it with umamitude, to make a burger executive class. At the lounge in Fifth Floor, David Bazirgan's cooks form the patty from ground short rib, chuck, and skirt steak — all cuts known for their deep flavor, as opposed to that namby-pamby sirloin — and well-larded with fat. They grill it so that it's pink and oozy in the center and grill-crisped on the outside. Then it's smothered in caramelized onions and melted comté cheese, and placed between a brioche bun so light you'd suspect the burger was levitating its way to your mouth if it weren't for the buttery taste of the bread. With fries and a drink (and tax and tip) in Fifth Floor's lounge, you'll pay $30. Pricey: yes. Worth it: that, too.