Preheat the oven to 350°.
Grate the zucchini and let it sit on a paper towel. The paper towel will absorb the moisture from the zucchini. Change the paper towel as needed while making the cake batter.
Using either a hand mixer or stand mixer, combine the butter, oil and sugar.
Mix in the egg, vanilla, milk and lemon juice until well combined.
Add in the flour, cocoa, soda, baking powder, cinnamon and salt. Mix thoroughly.
Change the paper towel underneath the zucchini one last time and squeeze the remaining liquid out of the zucchini.
Using a spoon, fold the zucchini into the cake batter.
Pour batter into a greased 9X9 pan.
Sprinkle the chocolate chips, brown sugar and chopped nuts on top of the cake.
Bake at 350° for 30-35 minutes or until a toothpick comes out clean.
Cool and then serve!