Puff pastry is a flaky light pastry made from laminated dough which is composed of dough and butter or other solid fat. The butter is put inside the dough which is repeatedly folded and rolled out before baking. The gaps that form between the layers left by the fat melting are pushed by the water turning into steam during the baking process.
The production of puff pastry dough can be time-consuming, because it must be kept at a temperature of approximately 16 °C to keep shortening from becoming runny. Also, the dough must rest in between folds to let gluten strands link up and retain layering. In commercially prepared puff pastry different types of fat are used.
Butter is the most common type used because it provides a richer taste. Specialized margarine formulated for high plasticity is used for industrial production of puff pastry.