Buttery homemade puff pastry only gets better with a touch of chocolate. Adding a little cocoa powder to the butter block transforms the pastry into a barely sweet, delicately chocolaty version of itself. The fat carries the flavor of the cocoa, dispersing it throughout the dough's layers. It makes an irresistible base for mille-feuilles, pinwheel cookies, and petit fours. This recipe is from cookbook author and baker Eddy Van Damme.