Heat your oven to 350°F and grease a 9x5 inch loaf pan thoroughly with cooking spray or butter, making sure to coat the bottom and all sides evenly. This prevents sticking and ensures even browning.

Whisk together the flour, salt, baking soda, and baking powder in a medium bowl, breaking up any lumps as you go. Set this dry mixture aside—it's ready to incorporate once the wet ingredients are prepared.

While the oven preheats, finely grate your zucchini on a box grater, then place it in a clean kitchen towel and squeeze firmly to remove as much moisture as possible—this prevents a soggy bread. In a separate large bowl, whisk together the sugar and lemon zest, rubbing the zest between your fingers to release the oils and awaken the bright flavor. Add the room-temperature eggs one at a time, whisking well after each addition, then pour in the vegetable oil and the 1 tablespoon of lemon juice. Whisk until the mixture is pale and well combined, which typically takes 1-2 minutes.

Pour the dry ingredient mixture from Step 2 into the wet ingredients from Step 3, then gently fold them together using a spatula just until combined—don't overmix, as this develops gluten and can make the bread tough. Add the vanilla extract and fold once more. Finally, gently fold in the squeezed zucchini until evenly distributed throughout the batter. I like to fold gently rather than stir vigorously because it keeps the bread tender and prevents the zucchini from breaking down too much.

Pour the batter into the prepared pan from Step 1 and smooth the top with a spatula. Bake for 45-50 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs clinging to it. The bread is done when the top is golden brown and the sides have started to pull slightly away from the pan.

Remove the bread from the oven and let it rest in the pan for 10 minutes—this allows it to set slightly and makes it easier to turn out. Turn the bread out onto a wire cooling rack and let it cool for at least 15-20 minutes before glazing. While the bread cools slightly, sift the icing sugar into a small bowl to remove any lumps, then whisk in the 4.5 teaspoons of lemon juice until you have a smooth, pourable glaze with a consistency similar to heavy cream.

Once the bread has cooled slightly but is still warm to the touch, slowly pour or drizzle the lemon glaze over the top, letting it pool and drip down the sides naturally. Let the glaze set for a few minutes before slicing and serving. I find that glazing while the bread is still slightly warm helps the glaze soak in just a bit, creating a more cohesive flavor.