Preheat the oven to 350 degrees Fahrenheit. Prep your loaf pan by greasing it or lining it with parchment paper.
In a medium bowl, combine the dry ingredients, including the flour, cinnamon, baking soda, baking powder, and salt. You can also add a pinch of nutmeg for additional flavor. Set aside.
In another small bowl, whisk the butter and sugar until it is light and fluffy. Add the vanilla and eggs.
Shred zucchini in a food processor or using a cheese grater. You can leave the skin on if desired.
Add the zucchini to the wet ingredients and mix to incorporate. Be careful not to overmix the batter.
Add the wet ingredients to the dry ingredients. Let the batter sit for 15 minutes.
Pour the batter into the prepared loaf pan and bake for 55 to 65 minutes or until a toothpick inserted comes out clean.
Let cool for 5 minutes before removing. Cool on a wire rack before slicing and serving.
Notes
If you are using freshly milled grains for this recipe, I recommend weighing the flour instead of using volume measurements. Grain mills vary greatly - some create very fine and fluffy flour, while others are a little more coarse. This makes volume measurements unpredictable. Using a kitchen scale and calculating the grams is much more reliable, ensuring you end up with a delicious end product.