Grease and flour two 4 x 8-inch bread loaf pans and line with parchment paper, cutting the short sides to fit and cutting the long sides so that the parchment extends over each side of the pan about 2-inches.
Using the large holes on a shredder-grater, grate the zucchini (leave the skins on, but remove the seeds).
Beat eggs in a large bowl until light and lemon-colored; add in canola oil, sugar, vanilla extract, and mix until smooth. Stir in grated zucchini.
In a separate bowl, whisk together the gluten-free all-purpose flour, cocoa powder, cinnamon, salt, baking soda, and baking powder.
Stir the flour combination into the zucchini mixture.
Fold in the chocolate chips, raisins, and chopped walnuts.
Pour the batter into the prepared loaf pans.
Bake at 350ºF for about 1 hour until the bread is firm to the touch and pulls away from the sides of the pan. A toothpick inserted into the center of the loaves should come out clean.
Transfer the pans to a wire rack and let cool in the pan for 10-15 minutes, carefully lift the loaves with the parchment onto the racks to cool completely before slicing to serve.
Save uneaten zucchini bread by wrapping it in plastic wrap, then storing in the refrigerator up to a week. To freeze, first, wrap the bread in plastic wrap, then wrap tightly in foil before placing in a freezer-safe zipper bag. 
 Slice the zucchini bread and place each slice with waxed paper wrapped on each side before packing to freeze. By doing it this way, it’s easy to remove a slice at a time to warm in the microwave and enjoy it at any time!