Castagnaccio is made with chestnut flour. Castagna is the Italian word for chestnut.
Apart from chestnut flour, Castagnaccio, is made with raisins, grated lemon peel, fresh rosemary, extra virgin olive oil, a little sugar, pine nuts and walnuts, mixed with water and made into batter, then baked.
The recipe for making castagnaccio is on a blog post I wrote in May 2011 – as you can see I have been making it for a very long time.
I am now using Australian chestnut flour rather than the Italian imported variety and both are quality products.
SEE: CASTAGNACCIO (A Tuscan sweetened bread made with chestnut flour)