Preheat your oven to 350°F (175°C) and grease a 9×5 inch loaf pan.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
In a large bowl, combine the sugar and lemon zest, rubbing them together with your fingers to release the lemon’s fragrance.
Add the softened butter to the sugar mixture and beat until light and fluffy.
Beat in the eggs one at a time, followed by the lemon juice and vanilla extract.
Stir in the grated zucchini, then add the dry ingredients alternately with the sour cream, beginning and ending with the dry ingredients. Mix until just combined.
Pour the batter into the prepared loaf pan and bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
