Preheat your oven to 325°F (165°C). Grease and flour two 9x5 inch loaf pans.
In a medium bowl, whisk together the flour, salt, baking soda, baking powder, cinnamon, and nutmeg. Set aside.
In a large bowl, beat the eggs, oil, sugar, and vanilla extract until well combined.
Fold the grated zucchini into the wet ingredients.
Gradually add the dry ingredients to the wet mixture, stirring until just combined. Be careful not to overmix.
If using, fold in the chopped walnuts.
Divide the batter evenly between the prepared loaf pans.
Bake for 60-65 minutes, or until a toothpick inserted into the center comes out clean.
Cool in the pans for 20 minutes, then remove from pans and cool completely on a wire rack.