Preheat oven to 350°F (176°C).
Use a box grater or food processor to shred the zucchini. You will want about ½ of a large zucchini or 1 medium zucchini. Place two paper towels under the grater. Then, grate the zucchini. Squeeze it with your hands to get out excess water. After grating and squeezing you will want 200g/7 ounces (scant 1 cup) of the zucchini.
In a large bowl whisk the all purpose flour, vital wheat gluten, protein powder, baking powder, cinnamon, and nutmeg until well incorporated. Then, add in the non-dairy milk, agave, and vanilla extract.
Mix with a spoon. A thick, partially wet dough will start to form.
Then, add in the grated zucchini and fold it in until the moisture of the zucchini makes the whole batter wet. It will be thick.
Pour the batter into a lined loaf pan. Spread it with a spoon in the pan. Sprinkle cinnamon over top if desired.
Bake for 50 to 60 minutes depending on your oven. A toothpick should come out clean.
Allow the zucchini bread to cool for 30 to 45 minutes before cutting. Enjoy immediately or keep stored in the fridge.