Puff pastry, also known as pâte feuilletée, is a flaky light pastry containing several layers of butter which is in solid state at 20 °C (68 °F). In raw form, puff pastry is a laminated dough composed of two elements: a « dough packet », the détrempe and a « butter packet » or other solid fat, the beurrage. Preparing a classic puff pastry requires an envelope formed by placing the beurrage inside the détrempe. An « inverse puff » pastry envelope places the détrempe inside the beurrage. The resulting paton is repeatedly folded and rolled out before baking.

The gaps that form between the layers left by the fat melting are pushed (leavened) by the water turning into steam during the baking process. Piercing the dough will prevent excessive puffing, and crimping along the sides will prevent the layers from flaking all of the way to the edges.

Puff pastry seems to be related to the Middle Eastern phyllo,and is used in a similar manner to create layered pastries. While traditionally ascribed to the French painter and cook Claude Lorrain who lived in the 17th century (the story goes that Lorrain was making a type of very buttery bread for his sick father, and the process of rolling the butter into the bread dough created a croissant-like finished product), references to puff pastry appear before the 17th century, indicating a history that came originally through Muslim Spain and was converted from thin sheets of dough spread with olive oil to laminated dough with layers of butter. The first known recipe of puff pastry as we know it nowadays (using butter or lard), appears in the Spanish recipe book Libro del arte de cozina (Book on the art of cooking) written by Domingo Hernández de Maceras and published in 1607 . Maceras, the head cook in one of the colleges of the University of Salamanca, already distinguished between filled puff pastry recipes and puff pastry tarts, and even mentions leavened preparations. Thus, puff pastry appears to have had widespread use in Spain by the beginning of the 17th century. The first french recipe of puff pastry was published in François Pierre La Varenne’s « Pastissier françois » in 1653.

The production of puff pastry dough can be time-consuming, because it must be kept at a temperature of approximately 16 °C (60 °F) to keep shortening from becoming runny, and must rest in between folds to allow gluten strands time to link up and thus retain layering.

The number of layers in puff pastry is calculated with the formula:

where l {displaystyle l} l is the number of finished layers, f {displaystyle f} f the number of folds in a single folding move, and n {displaystyle n} n is how many times the folding move is repeated. For example, twice-folding (i.e. in three), repeated four times gives ( 2 + 1 ) 4 = 81 {displaystyle (2+1)^{4}=81} (2 + 1)^4 = 81 layers. Chef Julia Child recommends 73 layers for regular pâte feuilletée and 729 (i.e. 36) layers for pâte feuilletée fine (in Volume II of her Mastering the Art of French Cooking textbook).

Commercially made puff pastry is available in grocery stores. Common types of fat used include butter, vegetable shortenings, and lard. Butter is the most common type used because it provides a richer taste and superior mouthfeel. Since shortenings and lard have a higher melting point, puff pastry made with either will rise more than pastry made with butter if made correctly; however it will often have a waxy mouthfeel and a blander flavor. Specialized margarine formulated for high plasticity (the ability to spread very thin without breaking apart) is used for industrial production of puff pastry.