Preheat your oven to 350°F (175°C) and coat a 9x5-inch loaf pan with cooking spray or line with parchment paper.

In a large mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, ground cinnamon, and ground nutmeg.

In another bowl, cream together the granulated and brown sugars with melted butter until well blended. Add the eggs one at a time, then mix in the zucchini, crushed pineapple, and vanilla extract until smooth.

Gradually add the dry ingredients to the wet ingredients, folding gently with a spatula until just combined. Fold in walnuts or pecans if desired.

Pour the batter into the prepared loaf pan and bake for 55-65 minutes. Check for doneness with a toothpick.

Remove from the oven and let cool in the pan for about 10 minutes before transferring to a wire rack to cool completely.