Preheat to 325°F (163°C). Spray an 8×4-inch loaf pan with baking spray with flour or grease and flour the pan.

Prepare the Zucchini: Grate zucchini using the large holes of a box grater. Wring or press out excess moisture, measuring 1 cup after squeezing.

Mix the Wet Ingredients: In a large bowl, mix together sugar, vegetable oil, egg, lemon extract, and lemon zest. Fold in the shredded zucchini gently.

Combine the Dry Ingredients: In a separate bowl, whisk together flour, salt, baking soda, and baking powder.

Add the dry mixture to the wet ingredients in two additions, folding by hand just until no streaks of flour remain. Do not overmix.

Bake: Pour batter into the prepared pan and bake for 45–50 minutes or until a toothpick comes out with a few moist crumbs.

In a small saucepan, heat sugar and lemon juice over low heat until the sugar dissolves. Brush the top of the cake with lemon syrup after it comes out of the oven.

Allow the cake to cool in its pan for 10 minutes, brushing with additional syrup while it cools. Remove from pan and cool completely.

In a small bowl, whisk together powdered sugar and lemon juice until smooth. Adjust for thickness and pour over cooled bread.