This rooftop terrace just off Puerta del Sol is in one of Madrid's oldest, most exclusive clubs (the casino, a club for gentlemen, not gamblers). The food is inspired and overseen by Ferrán Adriá, who runs his own famous restaurant, El Bullí, near Roses in Catalonia. Francisco Roncero's creations closely follow Adriá's trademarks: try any of the light and tasty mousses and foams or indulge in the unique tapas -- experiments of flavor, texture, and temperature. There's also a sampler menu. Reservations essential.