Preheat oven to 325. Grease a loaf pan and set aside.
In a mixing bowl, gently mix together zucchini, sugar, egg, oil, and lemon. Add dry ingredients and zest, stirring until just combined. Spread into prepared loaf pan.
Bake 45-50 minutes or until golden and cooked through (a slight touch on the center of the loaf should be firm and not give way). Remove pan from oven and cool on a cooling rack with parchment or wax paper underneath (to catch glaze drips) at least 15 minutes before turning loaf out of pan.
Meanwhile, to a small sauce pan add sugar and lemon juice. Turn heat on medium and bring to a boil, dissolving sugar. Turn off heat and stir in lemon zest.
Turn loaf out onto cooling rack. While loaf is still warm, brush glaze all over the top and sides of loaf, allowing excess to drip onto the paper underneath the rack. Allow loaf to cool completely and glaze to dry before slicing. Glaze will be shiny and tacky to the touch, but not wet.