Preheat oven to 350°F (175°C). Grease a 9×5-inch loaf pan or four mini loaf pans.
In a medium bowl, whisk flour, baking powder, and salt. Set aside.
In a large bowl, beat eggs, sugar, and oil until light and fluffy.
Stir in buttermilk, lemon zest, and lemon juice. Mix just until combined.
Add dry ingredients and grated zucchini to the wet mixture. Fold gently until no dry flour remains.
Pour the batter into your prepared pan(s).
Bake mini loaves for 30–35 minutes or a large loaf for 45–50 minutes. Test doneness with a toothpick.
Let the bread cool in the pan for 15 minutes, then transfer to a wire rack.
Once completely cooled, whisk together glaze ingredients and drizzle over the loaf.
Slice and enjoy.