Biscotti are twice baked cookies. They are baked once in a loaf, then again after they are cut apart in order to dry them enough to dip in a coffee or tea, and not have them fall apart. However, you can also eat them without dipping.
I originally started baking biscotti when I didn't like any of the recipes that other people made, and started experimenting. If you want, you can substitute some ingredients in this biscotti recipe, but be careful of not making the dough too runny, because then it will be very difficult to work with. Biscotti dough is a little tough, and I have managed to break several mixers making them. If you are going to make biscotti on a regular basis, I recommend buying a KitchenAid Artisan 5-Quart Stand Mixer KSM150. In my opinion, the KitchenAid KSM150 is the best choice for making biscotti.