What’s the difference between puff pastry sheets and phyllo dough? Can they be used interchangeably? —E.H., Washington, UtahPuff pastry dough is a rich dough made by placing chilled butter between layers of pastry dough. It is then rolled out, folded into thirds and allowed to rest. This process is repeated six to eight times, producing a pastry with many layers of dough and butter. Commercially prepared puff pastry dough can be used in recipes that call for homemade puff pastry dough, such as croissants. Phyllo (also spelled filo) dough is tissue-thin pastry dough used in a variety of sweet and savory Greek and Middle Eastern dishes. Although phyllo dough can be made by home cooks, it isn’t easy to do so. However, commercially prepared phyllo dough is a convenient alternative that results in a product that is as good as homemade. Phyllo dough can be used as a substitute for strudel dough or for other pastry wrappers, such as turnovers.Puff pastry dough and phyllo dough are very different and, if used interchangeably, will yield different results. Greek baklava made from puff pastry instead of phyllo, for example, would not be the same…whereas an apple turnover made with either dough would be more acceptable. It’s best to become familiar with each dough by using it for its intended purpose before you begin experimenting.