Heat oven to 350 degrees. Spray 4 mini loaf pans (6"x3 1/2") well with cooking spray. You can also use a 9x5 loaf pan.
In a small bowl combine the flour, baking powder, and salt. Stir with a whisk to break up any clumps. Set aside.
In a large bowl with a hand blender, or a bowl of a stand mixer, beat the eggs for 30 seconds. Add the sugar and oil and beat together until well combined. About 1 minute until it looks "fluffy" and pale in color.
Add buttermilk, lemon zest, and lemon juice. Blend together until mixed in.
Add the shredded zucchini and the bowl of dry ingredients into the wet mixture, and stir gently with a spatula or wooden spoon just until combined and no flour pockets remain.
Evenly divide the batter between the 4 mini loaf pans (or 9x5). Cook the mini loaf pans for 30-34 minutes and the 9x5 loaf pan for 40-45 minutes. The bread will look done and when gently pressed with a finger will spring back, a toothpick inserted in the middle will also come out clean.
Let cool for 10 minutes in the loaf pan and then remove the bread to a cooling rack to cool complete.
Mix together the powdered sugar and lemon juice with a fork until combined and it's the consistency you want. Add more lemon juice (or milk) if it's too thick and if it gets too runny, add a little bit of powdered sugar. Drizzle the glaze over the bread with a fork or put the glaze into a Ziploc bag and cut the corner.
I prefer the zucchini peeled so that's what I do, you can also just shred it with the peel on too.
You will need 2 fresh lemons for this recipe.
If you want less lemon flavor then use milk in the glaze recipe instead of the lemon juice.