Or crescentina modinese, a favourite in the Apennines south of Modena, and Emilia in general. Elsewhere they might be called tigelle, although some say that's the device resembling a French waffle iron used for cooking them. They are thin disks of dough made with lard and brewers' yeast. They're usually cut in half and filled with meat or cheese (or sometimes chocolate or Nutella, although this is regarded with horror by old time crescentinistas).
Anyone from Modena will tell you that the Bolognese don't know anything about cooking. What they call a 'crescentina' is really a gnocco fritto.
Images by: Città di Modena, PD Art