Prepare the Zucchini and Apple
Grate zucchini and apple using a box grater.
Place zucchini in a clean kitchen towel and squeeze out excess moisture.
Lightly drain apples if very juicy.
Mix the Batter
In a medium bowl, whisk together flour, baking soda, baking powder, salt, cinnamon, and nutmeg.
In a large bowl, whisk sugar, oil, applesauce, eggs, and vanilla.
Stir in grated zucchini and apple until evenly combined.
Gradually fold dry ingredients into wet mixture until just combined.
Fold in any optional add-ins like nuts, raisins, or chocolate chips. Avoid overmixing.
Bake the Bread
Preheat oven to 350°F (175°C).
Grease and flour a 9×5-inch loaf pan or line with parchment paper.
Pour batter into the pan and smooth the top.
Bake 50–60 minutes, until a toothpick inserted comes out clean.
Cool in pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.