Preheat your oven to 325°F (165°C) and prepare two 8x4 inch loaf pans by greasing and flouring them.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.

In a large bowl, rub sugar with lemon zest, then add eggs, oil, lemon juice, and vanilla extract. Whisk until smooth.

Gradually fold the dry ingredients into the wet mixture until just incorporated.

Gently fold in the grated zucchini until evenly distributed.

Divide the batter between the prepared pans and smooth the tops.

Bake for 60-65 minutes, checking for doneness with a toothpick.

Let the loaves cool in the pans for 15 minutes before transferring to a wire rack.

Whisk together powdered sugar and lemon juice for the glaze until smooth.

Drizzle the glaze over the cooled loaves and let it set before slicing.