Preheat your oven to 180° C (350° F), get out a 9x13 inch baking pan and grease with butter or cooking spray.
In a mixing bowl, add the flour, cinnamon, salt, baking powder, and baking soda, whisk together. Set aside.
In another mixing bowl, add the eggs, both sugars, and oil. Beat with an electric mixer until well mixed and creamy.
Using a large sturdy spoon, mix in the flour mixture.
Mix in the zucchini.
Spread mixture into the prepared baking pan.
Bake for 30 minutes. Cool in the pan on a wire rack until completely cooled.
Prepare the frosting by adding the cream cheese, butter, and vanilla in a mixing bowl, mix with an electric mixer until smooth.
Gradually add the powdered sugar and beat in with the mixer, until all the sugar is added. Beat on high speed to make a light and fluffy frosting.
Spread the frosting over the "bars".
Slice into bars, serve, and enjoy.