This comes from Italy, where these cookies are usually dunked in coffee. The name means "twice cooked" in Italian, and this recipe leaves little doubt as to why.
Combine all the ingredients in a mixing bowl and stir to combine. When the dough becomes too stiff to stir, work with your hands until the ingredients are thoroughly combined. Divide into 4 parts and roll each into a log about 1 inch thick.
Place 2 logs on each of 2 baking sheets which have been covered with parchment or wax paper.
Bake in a preheated 350 degrees F oven for about 30 minutes, until lightly browned.
Remove from the oven and leave the oven turned on.
Cut into 1/2 inch slices while still warm and return to the oven.
Bake an additional 10 to 15 minutes, until crisp and golden brown.