Puff or flaky pastry (pâte feuilletée) (Slideshow version)
Puff pastry is an incredible assembly of thin layers of butter enclosed in thin layers of dough. After cooking this give a succession of thin crisp pastry leaves that produce exceptional desserts or pies. It's a jewel of French patisserie.
Making your own puff pastry is not very difficult, it's just a little work with a good recipe (like this one!). This recipe is for quick puff pastry ("feuilletage rapide") perfect for beginners.