Preheat oven to 350 degrees Fahrenheit. Butter and flour an 8x4-inch loaf pan. Set aside.

In a medium mixing bowl whisk the flour, baking powder, and salt. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, mix the sugar and lemon zest until fragrant; about 30 seconds. Add oil, eggs, sour cream, and lemon juice. Mix.

Add flour mixture. Mix gently until flour is about halfway incorporated. Fold in zucchini with a spatula until flour leaves only a few streaks. Do not over-mix. Pour batter into the prepared loaf pan.

Bake for 40 to 45 minutes, until a toothpick inserted into the center comes out clean. Let cool in the pan for a few minutes, then invert bread onto a wire rack to cool completely.

Once loaf is cool, mix glaze ingredients in a bowl with a whisk and drizzle over the top; let set. Slice and serve. Store bread in an airtight container.