Biscotti di Prato

These crisp, dry almond biscuits named in honor of Prato, near Florence, are also known as cantucci and cantuccini. They are usually served with a glass of sweet Tuscan wine called vinsanto (holy wine), so that they may be dipped in the wine to soften. The dry texture comes from the leavener used — bicarbonate of ammonia. It works in a way similar to baking powder but has a side effect of promoting the complete desiccation of the dough during baking. Sometimes referred