Preheat oven to 325 degrees. Spray a 9x5 bread pan with cooking spray and set aside.
Place the shredded zucchini in a large mesh strainer and press on it thoroughly. Press as much liquid out of the zucchini as you can.
In a large bowl, whisk together the brown sugar, oil, eggs and vanilla. Fold in the drained zucchini, ground nuts and sage (if using).
In a separate bowl, whisk together the flours, cinnamon, salt, baking soda and baking powder.
Stir the flour mixture into the sugar and zucchini mixture until well combined.
Pour the bread batter into the pan. Sprinkle the top of the loaf with the tablespoon of sanding sugar.
Bake the loaf for 60 - 70 minutes or until loaf springs back when lightly touched and/or a toothpick inserted into the center of the loaf comes out clean.
Allow the loaf to cool for about 15 minutes in the pan. Remove to a cooling rack and allow to cool completely before slicing and serving.