You can use shortening instead of butter in puff pastry, but the results will be different. Shortening is more dense than butter, so your pastry will be more dense as well. The flavor will also be different, since shortening is flavorless and butter has a distinct flavor.
You can also use special puff pastry shortening. Because of its flavor and melt-in-the-mouth texture, butter is the best fat for rolling in. Because puff pastry contains few ingredients (flour, butter, water, and salt), it does not come with a lot of flavor. Make sure to use the best possible ingredients in your recipe. If you used shortening instead of butter, the results would almost certainly be a puff pastry made of bread. You don’t have to shorten for it to be bad if you use non-hydrogenated versions. Working with butter requires a good deal of control over temperature, so concentrate your energy on this aspect of the process, which will allow you to develop a sense of mastery.
When substituting fats, make sure to use the same amount as in your recipe. It will also ensure that the flavors and textures of the recipes are the same. You will also be able to reduce the amount of unhealthy fats in your diet if you consume the same amount of fats.