filo or fillo dough
Phyllo is a tissue-thin dough used widely in Mediterranean and Middle Eastern cooking. Made from flour, water, and a little bit of oil, paper-thin sheets of phyllo dough are usually layered and brushed with butter to create that characteristicly crisp, flaky, golden-brown pastry we see in popular dishes like spanakopita and baklava.
Phyllo dough is not to be mistaken for puff pasty, which is also commonly sold frozen. Both are flaky and crisp, but puff pastry is buttery, soft, and of course, puffy, where phyllo dough is not. The two are generally not interchangeable.
Frozen phyllo can be stored for up to a year. Just leave yourself enough time to thaw it overnight in the refrigerator before using. Do not attempt to refreeze phyllo, it will become brittle.