Preheat the oven and prepare the pan: Preheat your oven to 350°F (175°C). Grease and flour a 9x5-inch loaf pan, or line it with parchment paper for easy removal.

Mix the dry ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, and nutmeg. Set aside.

Beat the eggs and sugars: In a large bowl, beat the eggs, granulated sugar, and brown sugar until well combined. Add the vegetable oil and vanilla extract, and mix until smooth and incorporated.

Combine the wet and dry ingredients: Gradually add the dry ingredient mixture to the wet ingredients, stirring until just combined. Be careful not to overmix. The batter may be slightly lumpy.

Add the zucchini and nuts: Gently fold in the grated zucchini and chopped nuts (if using), ensuring they are evenly distributed throughout the batter.

Bake the zucchini bread: Pour the batter into the prepared loaf pan, spreading it evenly. Bake in the preheated oven for 50-60 minutes, or until a toothpick inserted into the center comes out clean. If the top of the bread starts browning too quickly, you can tent it with foil during the last 10-15 minutes of baking.

Cool and serve: Once baked, remove the zucchini bread from the oven and let it cool in the pan for about 10 minutes. Then, transfer the bread to a wire rack to cool completely before slicing. Serve at room temperature and enjoy the delightful flavors of this homemade zucchini bread.