Preheat oven to 350°F and grease a 9 x 5 inch loaf pan.
In a mixing bowl, beat together sugar and eggs until blended.
Add vanilla and oil and beat until smooth.
In a medium bowl whisk together flour, baking powder, baking soda, and salt. Slowly add to the egg mixture, mix until smooth.
Fold in zucchini, lemon zest, and 2 tablespoons lemon juice.
Pour the batter into the prepared loaf pan and bake at 350°F on a middle rack until a toothpick in the center comes out clean, approximately 50 minutes.
Let the loaf cool completely.
Combine glaze ingredients and spread over the loaf letting it drizzle down the sides.