Preheat the oven to 350 degrees F. Grease a 9×5 inch loaf pan with butter or cooking spray and set aside.
In a large bowl, mix together the flour, baking powder, baking soda, salt, nutmeg, cinnamon and cloves. In a separate medium bowl, cream together the butter and sugar until light and fluffy.
Add the eggs, one at a time, beating well after each addition. Then add in the vanilla. Slowly beat in the dry ingredients until just combined. Do not overmix or it will make your bread tough.
Fold in the shredded zucchini and chopped walnuts until just combined. Pour the batter into the prepared pan and spread it evenly.
Bake for 55-60 minutes, or until a toothpick inserted into the center of the bread comes out clean. Let cool for 10 minutes before removing from the pan and transferring to a wire rack.