In a small bowl, whisk together the all-purpose flour, baking powder, and salt until combined. Set aside.
2 cups all-purpose flour, 2 teaspoons baking powder, ½ teaspoon table salt or fine sea salt
In a large bowl, or use the bowl of a stand mixer, beat the eggs on medium-high speed for 30 seconds.
2 large eggs
Add in the sugar and oil, and continue beating on medium speed until well combined, and until it's "fluffy looking" and pale in color; about 1-2 minutes.
1 cup granulated sugar, 1/2 cup canola or vegetable oil
Add in the buttermilk, lemon zest, and lemon juice and blend together just until combined.
1/2 cup buttermilk, zest of 1 lemon, 2 tablespoons fresh lemon juice
Add the dry ingredients into the wet ingredients along with the shredded zucchini. Beat on low speed, or mix in by hand using a mixing spoon or spatula, just until combined and no flour streaks remain in the batter.
1 cup shredded zucchini
Evenly divide the lemon zucchini batter between the mini loaf pans (or just dump it all into the large loaf pan if using).
Cook the mini loaf pans for 30-34 minutes OR the large loaf pan for 45-50 minutes. The bread should look done, and when gently pressed with a finger the bread should spring back, and a toothpick inserted into the middle should come out clean or with moist crumbs (not wet batter!).
Let the bread cool for about 15 minutes inside the warm loaf pan, and then remove the bread from the loaf pan and place the bread loaf on a wire cooling rack to cool completely.