Two terms you’ll be glad you know when it comes to making your own croissants:
Proofing: Yeasted breads, like croissants, are usually “proofed” after the dough has been shaped. The proofing step allows the dough to rise more and develop in flavor. Proofing is usually done in a warm environment—75° to 80°F—which encourages the yeast to grow and multiply.
Laminated dough: Croissants, Danish, and puff pastry are all made from laminated dough—thin sheets of dough layered with thin sheets of butter. There are two steps to laminating dough: First, encasing butter in a dough “envelope,” and second, rolling and folding the dough. Depending on the type of pastry, the rolling and folding step is repeated two to six times.
During baking, the steam generated by the moisture in the butter is trapped, lifting and separating the individual dough layers. The resulting lofty layers (as many as 1400 for classic French puff pastry) bring an airy lightness to the finished baked good.