 He later opened a gourmet Burger Bar in Las Vegas, Nevada, which features a $60 "Rossini Burger" made of American Kobe beef, sautéed foie gras, and shaved truffles.Shortly thereafter he opened a second Fleur de Lys, at Mandalay Bay.Chef Keller also opened a French influenced steakhouse in Downtown St. Louis called SLEEK, which is regarded as the best steak house in St. Louis.