What should I do with candied citron?
Well, if it comes directly from Southern Italy you could use it to make some Southern Italy specialty like pastiera napoletana, sfogliatelle napoletane or cannoli siciliani, all of which require candied fruits.

Traditionally pastiera is done with a mix of candied citron and orange peel plus candied pumpkin (cucuzzata) which however is not the easiest ingredient to find.  

Citrus is definitely a must for sfogliatelle. There are two types of sfogliatelle ricce and frolle. Sfogliatelel ricce are better tasting in my opinion, but can be challenging to do at home.


Sfogliatella riccia


Sfogliatella frolla

Cannoli traditionally only have candied orange peels, but I guess citron would do well in them anyway. 


Cannolo siciliano

Note: the pastry in the Wikipedia photo for pastiera seems way too thick and crumbly. The pastry should be very thin, there just to keep everything together, and should not be the dominant taste.