Freezing croissants before baking is not mandatory, but it is a common practice in commercial bakeries and home baking to improve the texture and rise of the croissants. Freezing croissants before baking allows the dough to rest and develop more flavor, and it also helps the layers of butter and dough to separate better during baking, resulting in a flakier and more delicate texture.
When you freeze croissants before baking, it's a process known as "retarding" or "proofing." The croissants are shaped and then placed in the freezer before they are fully proofed. This slows down the yeast activity and fermentation, so when you take the croissants out of the freezer and let them thaw and proof at room temperature or in the refrigerator, they have a more controlled rise and develop better flavor.
However, if you don't have the time or prefer not to freeze the croissants, you can still bake them directly after shaping. Just make sure to allow them to proof sufficiently at room temperature before baking. The result might be slightly different, with potentially less flakiness, but they should still be delicious.
To sum up, freezing croissants before baking is not mandatory, but it can be a helpful technique to achieve the best texture and flavor in your croissants. If you choose not to freeze them, make sure to proof them adequately before baking for satisfactory results.