Chef Hubert Keller, owner of Fleur de Lys in Mandalay Bay is responsible for creating one of the world’s most expensive hamburgers, a decadent burger For the amazing price of $5,000 may enjoy the FleurBurger 5000; a Kobe beef patty, which comes with a side of black truffles served on a brioche truffle bun, containing foie gras and a truffle sauce made from more truffles. The meal is paired with a superb bottle of Chateau Petrus 1990, and a side of fries may be possible but that’s unconfirmed.