Judge for yourself at this tiny temple to chocolate cake. Carlos Lopes, a Portuguese restaurateur, devised the "best" recipe. It's creamy with chocolate mousse and crispy with layers of chocolate meringue—and coated with a gloss of ganache. Cakes are sold whole or by the slice. For an extra dollop of decadence, add a scoop of super-rich ice cream from Il Laboratorio del Gelato. There are also toasted sandwiches (Portuguese ham and cheese on ciabatta), hot or iced chocolate drinks, strong coffee and organic double-dark-chocolate tea.