Preheat oven to 325 degrees F (165 degrees C). Grease and flour a 9x5 inch loaf pan.
In a large bowl, combine flour, baking soda, baking powder, salt and cinnamon. In a separate bowl, beat eggs, oil, sugar and vanilla until blended. Add to flour mixture, stirring just until all dry ingredients are moistened. Fold in zucchini and walnuts (if desired). Pour into prepared pan.
Bake for 55 to 60 minutes, or until a wooden toothpick inserted into the center of the loaf comes out clean. Let cool in pan for 10 minutes, then turn out onto a wire rack.
Interesting Facts
Zucchini is a type of summer squash that is commonly used in baking.
Zucchini bread is often served as a dessert, but can also be served as a snack or breakfast treat.
It is important to not overmix the batter, as this can cause the bread to be tough.