Puff pastry rises with no yeast at all, only steam trapped in butter
Puff pastry contains no raising agent. Cooks fold slabs of butter into flour-and-water dough again and again, building hundreds of separate sheets. In the oven, water in the fat turns to steam and pushes every layer apart. Julia Child's full method produces 729 of them.
The French call it pate feuilletee. A plain dough, the detrempe, is wrapped around a block of solid fat, the beurrage, then rolled out, folded, rested and rolled again. Each round multiplies the layers: folding in three and repeating the move four times gives a great many sheets, and Child's quicker rough puff still manages 72. Between turns the dough is chilled to about 16 degrees Celsius so the butter stays solid, rested so the gluten can relax, and rotated ninety degrees before the next rolling.
France developed the modern version in the seventeenth century, but the idea is older. A charter from Robert, bishop of Amiens, in 1311 contains the earliest known French recipe for flaky pastry. Spain got there early too, probably drawing on Moorish technique: Domingo Hernandez de Maceras, cook at a Salamanca college, printed recipes in 1607 that already distinguished filled puff pastries from tarts, and the royal chef Francisco Martinez Motino used it heavily for savoury game pies in 1611. The first recipe explicitly describing the butter-folding method, called tourage, appeared in La Varenne's Le cuisinier francais in 1651, and chefs including Antonin Careme later refined it.
A favourite story credits the painter Claude Gellee, known as Lorrain, who as an apprentice baker in 1612 supposedly rolled butter into bread dough for his sick father. There is almost no evidence for it, and it survives purely as kitchen folklore.
The choice of fat changes the result. Butter gives the best flavour and texture, while lard and vegetable shortening melt at higher temperatures and so rise more, at the cost of a waxy, bland bite; factories use a special margarine that spreads very thin without tearing. Short-cut blitz or rough-puff recipes scatter or grate the butter instead of using one block, which brings them closer to filo. Filo is layered only just before baking, brushed sheet by sheet with fat, and puffs far less because it holds less water.
Source: Puff pastry
