Preheat your oven to 350°F (175°C) and grease a 9x5-inch loaf pan or line it with parchment paper.
Grate the zucchini and lightly squeeze out excess moisture with a clean towel or paper towel.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, and nutmeg.
In a separate large bowl, beat the eggs, then mix in sugar, oil (or melted butter), and vanilla until smooth.
Fold the dry ingredients into the wet mixture gradually. Stir in the zucchini and nuts, if using, until just combined. Avoid overmixing.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 50–55 minutes, or until a toothpick inserted in the center comes out clean or with a few crumbs.
Let the bread cool in the pan for 10–15 minutes, then transfer to a wire rack to cool completely before slicing.