Preheat your oven to 350°F (175°C) and prepare a 9x13 inch baking pan by greasing it and dusting with flour.

Cream together softened unsalted butter and granulated sugar until light and fluffy.

Add eggs one at a time, mixing well after each. Stir in vanilla extract.

In a separate bowl, whisk together flour, baking soda, salt, cinnamon, nutmeg, and cloves.

Gradually mix dry ingredients into creamed mixture and fold in grated zucchini.

Pour batter into prepared pan, spreading evenly. Bake for 25-30 minutes.

Let baked bars cool completely on wire rack before frosting.

Mix powdered sugar and milk in a bowl until smooth, then frost cooled bars.

Cut into squares and serve.