Step 1: Preheat your oven to 350°F (175°C). Lightly grease and flour a 9×5-inch loaf pan or line it with parchment paper for easy removal.
Step 2: In a large mixing bowl, whisk together the eggs, applesauce, granulated sugar, brown sugar, and vanilla extract until smooth and well combined.
Step 3: Add in the shredded zucchini (make sure you’ve squeezed out the excess moisture), carrots, and apple. Mix gently until the mixture is evenly combined.
Step 4: In a separate medium bowl, whisk together the all-purpose flour, baking powder, baking soda, cinnamon, nutmeg, and salt. This ensures all dry ingredients are evenly distributed.
Step 5: Gradually stir the dry ingredients into the wet mixture, a little at a time. Mix just until everything is combined; avoid overmixing to keep the loaf tender.
Step 6: If using, fold in the chopped walnuts, pecans, raisins, or dried cranberries into the batter.
Step 7: Spoon the batter into your prepared loaf pan, using a spatula to smooth the top for even baking.
Step 8: Place the loaf pan in the preheated oven and bake for 55 to 65 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs. If the top browns too quickly, loosely cover with foil for the last 15 minutes.
Step 9: Let the bread cool in the pan for about 10 minutes, then transfer it to a wire rack to cool completely before slicing. This helps it set and makes for easier cuts.