Preheat the oven to 350 degrees F.

In a large mixing bowl, stir together the flour, sugar and baking powder. In a separate bowl, whisk together the eggs, yolks, and Nocello. Add the wet ingredients to the dry and stir just until the dough comes together, about 1 minute. Add the walnuts and mix until just incorporated.

Roll the dough into 3 logs, about 10 inches by 2 inches and place on an ungreased baking sheet. Bake 20 minutes until light golden brown and remove from oven. As soon as they are cool enough to handle, cut the logs on a slight diagonal into pieces 1/3-inch thick and arrange, cut side down, on the sheets. Reduce the heat to 275 degrees F., return the pieces to the oven and bake 20 minutes longer, until crisp and dry. Allow to cool.