Preheat oven to 350 F.
Prepare the pan with butter (or cooking spray)
Cut zucchini into manageable lengths and scoop out seeds. Use a box grater to grate 2 cups. Set aside.
In a large bowl, whisk together apple sauce, sugars, vanilla and egg. Set aside.
In a medium bowl, mix together flour, baking soda, baking powder, spices, and salt. Add to wet ingredients. Mix together and fold in grated zucchini.
Pour mixture into prepared pan. Bake for 55 - 60 minutes. At the the 45 minute mark, insert a toothpick to check for doneness.
Remove from oven and let cool 15 minutes before inverting onto a plate.
Let the cake completely cool before glazing.
Glaze: Mix all ingredients together and drizzle over cake. The leftover amount can be used to pour over individual pieces after serving.