Christmas cake filled with fruit and nuts
The name comes from sponge, but it has nothing to do with sponge cake (pan di spagna). First documented as a gift sent to the Duke Francesco Sforza of Milan in 1454, it is a round flat cake made of a short pastry, filled with apple and pear jam, raisins, pine nuts, almonds and candied fruit, then sometimes stamped with a design and baked, and sometimes covered with powdered sugar. There are many variations: Busseto (Verdi's hometown), Parma, Reggio Emilia and Piacenza each proudly claim their own.
Also known as spunghèda, spungada and spungä.