Preheat oven to 350 degrees F. Spray 13x9 baking dish with non-stick cooking spray and lightly dust with flour.
Grate zucchini, set aside.
In a large bowl, stir together sugar, vanilla extract, oil and eggs .
In a medium bowl, whisk together flour, baking soda, salt, cinnamon, nutmeg and cloves. Add dry ingredients to wet ingredients and mix until smooth.
Stir in zucchini and nuts if using.
Pour mixture into prepared baking dish
Bake for 35-40 minutes or until toothpick inserted comes out clean
Remove from oven to cooling rack. Cool completely
Now lets make the frosting! In a large mixing bowl add cream cheese, and beat until smooth. Add in butter, and beat until smooth and creamy. Gradually add powdered sugar, mixing in between each addition. Beat in vanilla extract until smooth.
Spread frosting onto cake with an offset spatula (you may have some frosting leftover)
Serve immediately or store in airtight container in refrigerator