Preheat the oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.

In a large mixing bowl, whisk together the granulated sugar, brown sugar, and vegetable oil until well combined.

Add the eggs and vanilla extract, and mix until smooth.

In another bowl, combine the flour, baking soda, baking powder, cinnamon, nutmeg, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Fold in the grated zucchini until evenly distributed.

Pour the batter into the prepared baking pan and smooth the top.

Bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cake to cool completely in the pan on a wire rack.

In a mixing bowl, beat the softened cream cheese and butter together until smooth and creamy.

Gradually add the powdered sugar and vanilla extract, mixing until well combined and fluffy.

Once the cake is completely cool, spread the cream cheese frosting evenly over the top.