Il panino con la milza is a traditional street food from Palermo, Sicily.  In Sicilian, it is called pani câ meusa.  It is prepared with the spleen of veal that has been boiled.   When you order one of these sandwiches, the boiled spleen is fried in lard then served in a sesame seed bread bun known as vastedda.  If you wish, you can have ricotta or thin strips of caciocavallo cheese added to the filling.  

                                                             BUON APPETITO!