Toast 1 cup walnuts for 8 minutes at 325 degrees. Then coarsely chop them up.
In a large mixing bowl, measure out and whisk together 2 1/2 cups white flour, 2 cups whole wheat flour, 1 1/2 cups granulated sugar, 2 tsp. baking powder, 2 tsp. cinnamon, 1/2 tsp. ground cloves, 1/4 tsp. ground ginger and 1 tsp. salt.
In a smaller bowl, whisk together 14 oz. of canned pumpkin, 3 large eggs and 2 tsp. maple flavoring.
Spoon the wet mixture into the bowl of dry ingredients and mix with the spoon. Using your hands, work in the chopped walnuts so to evenly distribute them.
Lay down some parchment paper on a large cookie sheet and form the dough into one log (13 inches in length / 5.5 inches in width at it's widest point / 1 inch thick ).
Bake the log in a preheated 350˚ Ffor 45 minutes or until firm to the touch. Then take it out and let it cool for 15 minutes.
Slice the log into 1/2 inch slices and stand the slices up on the cookie sheet.
Rebake at the same temperature for another 25-30 minutes. The longer you bake, the crunchier they will be.
When cooled thoroughly, melt white chocolate in a shallow dish and coat one side of each biscotti.