Preheat the oven to 350°F (175°C). Grease a 9×5-inch loaf pan and line it with parchment paper, leaving an overhang for easy removal.
In a medium bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, nutmeg, ginger, and cloves until well combined.
In a large bowl, whisk the granulated sugar, brown sugar, and vegetable oil until combined.
Add the eggs one at a time to the sugar and oil mixture, whisking well after each addition.
Stir in the pumpkin puree and vanilla extract until smooth.
Fold the dry ingredients into the wet ingredients gently until just combined; do not overmix.
Fold in the chopped apple, grated zucchini, and walnuts (if using) until evenly distributed.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake for 55 to 65 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs.
Remove the bread from the oven and let it cool in the pan for 15 minutes.
Using the parchment paper overhang, lift the bread out of the pan and transfer it to a wire rack to cool completely before slicing.