Preheat your oven to 350°F (175°C). Grease a 9×5 inch loaf pan and lightly dust with flour, tapping out the excess, then set it aside.

Grate the zucchini using the large holes of a box grater. Place it in a clean kitchen towel and gently squeeze out some excess moisture so it’s not soaking wet.

In a large bowl, whisk together the flour, baking soda, baking powder, cinnamon, nutmeg, and salt until combined and evenly speckled.

In a separate medium bowl, whisk the eggs, granulated sugar, and brown sugar until smooth and slightly pale, about 1 minute. Add the vegetable oil and vanilla extract and whisk again until fully blended.

Pour the wet ingredients into the dry ingredients and stir with a spatula until just combined, leaving a few small lumps. Fold in the grated zucchini until evenly distributed.

Fold in the chopped walnuts and/or raisins if using, distributing them through the batter without overmixing.

Pour the batter into the prepared loaf pan and smooth the top. Tap the pan gently on the counter to release any air bubbles.

Bake at 350°F (175°C) for 55–65 minutes until a toothpick inserted into the center comes out clean or with just a few moist crumbs. Look for a deep golden-brown top with a slight crack down the center.

Remove the loaf from the oven and let it cool in the pan for 10 minutes. Then transfer to a wire rack to cool completely before slicing so the crumb sets cleanly.

Slice thick and serve as-is, or spread with salted butter if desired.