Mix in walnuts first, then add the dry ingredients.
Beat/wiz just until just combined.
At this point, transfer batter to a separate bowl and refrigerate until the batter becomes very firm. Leaving it overnight is fine.
SHAPING THE BISCOTTIS
Preheat the oven to 350ºF
When the batter is completely firm, divide it into thirds.
Roll each third into a log no wider than 1 1/2 inches wide. The reason is because when the logs bake, they will spread surprisingly.
Place the three cold logs onto a lightly greased or sprayed sheet width wise, or place two logs lengthwise and the third log on a separate sheet.
Bake at 350F for approximately 20 minutes.
It is critical at this point that the logs are backed thoroughly because when you cut them into biscotti, they will have to hold their shape. If when you touch them, they offer resistance and feel firm, they should be done. If the logs are just under, they will be soft and will compress when cut them, and the final cookie will be misshapen.
Let cool completely before cutting.
CUTTING THE BISCOTTI
Place the serrated knife on an angle, making sure that the blade will hit the board perpendicular. Make your first clean slice at one end of the baked log. Place you knife at about 3/4 inch from your cut edge and once again, ensuring that the blade is perpendicular and parallel, make your next cut. Take your time as this step will define the overall outcome of the biscotti. Continue in the manner until all three logs are cut.
FINAL BAKING FOR THE BISCOTTI
Stand the biscotti on their bottom edge and bake at the same temperature (350ºF degrees) for about 10-20 minutes.
They will be slightly browned.
Baking them past this point will toast them too deeply, and the bright lemon flavour will begin to disappear under the dark and dry texture.