Puff pastry, croissants, and flaky pastry all rely on a mathematical phenomenon to achieve their many-layered structure. We cracked the code.
Puff pastry, croissants (see related recipe), and the flaky pastry we created for our vegetable tart recipes (see related recipes) all rely on a mathematical phenomenon to achieve their many-layered structure. These so-called laminated pastries, which are made up of alternating layers of dough and fat, are created by repeatedly rolling and folding the dough over itself, typically in thirds (like a business letter). Each set of folds is called a turn, and with each turn the number of layers increases exponentially rather than linearly. Thus, the first turn gives three (31) layers, the next nine (3 x 3, or 32), then 27 (3 x 3 x 3, or 33), then 81, and so on. Just eight turns (in our tests, the highest number possible before the layers got so thin that they melded together) create an astonishing 6,561 layers.