Long long ago, before the lemon was a twinkle in mother nature’s eye, there was the citron. One of the four original citrus fruits, from which all the others developed naturally, or otherwise, the citron (citrus medicus)—cedro in Italian—looks like a large, knobbly lemon, but is in fact a distinct fruit. When you cut a citron open, the similarities continue, but instead of having a thin white pith surrounding sunny, juice-filled segments, you have a tiny central section with pith and skin a couple of centimetres thick. Not very efficient for juicing, which is why the lemon was developed.
However, human ingenuity knowing no bounds, we quickly found a way to eat the bitter pith and rind of the citron: when cooked in sugar, the whole thing turns a translucent green, and loses its bitterness. Perfect as candied peel.
You see candied citron used in recipes up and down Italy, especially in the south where you see it decorating such classics as cassata siciliana. However, it is also one of the compulsory ingredients for panforte. The regulations for Panforte di Siena IGP, state that 35-45% of the mixture must contain candied peel and that 25% of that candied peel must be citron.
Here in Italy you can buy candied cedro already cut into chunks, or whole or halved allowing you to choose how you cut it.
Cedro is actively cultivated in Italy today, mostly in Calabria where, which even has a town named after it, Santa Maria del Cedro, at the centre of an area known as the riva dei cedri (the Citron Riviera).