Phyllo dough is a thin, unleavened pastry made from flour, water, and a small amount of oil or vinegar. It is known for its delicate, flaky texture and is commonly used in Mediterranean and Middle Eastern cuisines. The dough is rolled out into paper-thin sheets, which can be layered to create a crispy crust when baked. This versatile ingredient is often used in dishes like baklava, a sweet dessert filled with nuts and honey, and spanakopita, a savory pie filled with spinach and feta cheese. Phyllo dough can be found in the frozen section of grocery stores, making it accessible for home cooking.