The magic of this particular recipe can be found in its mixture of 50% Italian “00” flour* (which is lower in gluten than most American flours, it's an exceptionally light, almost powdery flour that yields dough that is softer and suppler and easier to work with) and 50% Farina di Semola (finely ground, pale yellow, hard durum wheat flour for making pasta and some bread). It can be a little tricky to find 00 flour in some regions but chances are you'll find it at most specialty stores, some grocery stores, and, natch, online.