Shred 1 cup of raw zucchini using a food processor.
Prepare brownie mix according to package but use half the amount of water since the zucchini will be watery. I use 3 eggs and also coconut oil instead of vegetable oil. Add the shredded zucchini to your brownie batter and stir until completely mixed in.
Transfer batter into a greased baking pan (grease with coconut oil), and bake according to package.
While the brownies are baking, prepare the chocolate buttercream frosting per my other recipe (see link in ingredients list). Stir cream cheese into the frosting.
When brownies are done cooking, allow them to cool completely before spread on the chocolate cream cheese frosting. Store brownies at a cool room temperature to prevent frosting from melting or hardening.