Pastry made with phyllo dough.
Don't Bother Buying Frozen Puff Pastry If It's Not All Butter

Frozen puff pastry is considered an acceptable shortcut even among some pro pastry chefs. The key is looking for a product labeled "all-butter."

Some store-bought puff pastry brands use vegetable oil rather than butter, creating a less satisfying taste and texture.

All-butter frozen puff pastry tastes richer and more like homemade. Pastry made with vegetable oil may be flat, underwhelming, and less pleasant overall.

Butter is a leavening agent, releasing water content and creating steam. This steam creates pockets of air as the sheets of dough are pushed apart, creating light, flaky layers.