A traditional cake/bread made at Christmas time, panettone was created in the Lombardy region and it is the undisputable holiday favorite. Scholars have traced panettone back to the middle ages. The dome shaped sweet bread is traditionally made with candied fruits, raisins and flavored with liquors. Today you can find it with chocolate chips and other ingredients. It is less like a cake then light fluffy sweet bread. The use of natural yeast results in the dough that rises slowly. The rising time can be as long as 48 hours. The long leavening contributes to the long shelf life, which can be as long as 6 months. Italian bakers take pride in the age of their leavening and some are maintained over many years.

 http://turosdolci.wordpress.com/2009/10/19/panettone-a-traditional-sweet-bread-is-a-symbol-of-christmas-greetings/ [1]