Factory-made frozen croissant dough became fast-food practical in the late 1970s. The innovation allowed shops to bake shaped, unbaked pastries on site without employing highly trained pastry chefs for every production step.
Croissant dough is laminated: yeast-raised dough is folded around butter repeatedly to create thin alternating layers. Commercial freezing made it possible to separate preparation from baking, so suppliers could produce the dough centrally and retailers could finish it fresh throughout the day.
This change helped create the modern croissanterie, a bakery-café format associated with quick service and takeaway food. It was often described as a French response to the spread of American-style fast food, adapting convenience and speed to a traditional French pastry.
Frozen dough does not necessarily mean a croissant was baked in advance. Many products are delivered frozen, then thawed, proofed, and baked at the point of sale. The common mix-up is treating “frozen” as synonymous with “already baked.”