Preheat oven to 350°F and line a 9x13 inch baking pan with parchment paper.
In a large bowl add flour, sugar, cocoa powder, baking soda, salt. Whisk until evenly mixed.
Add in oil, vanilla. Stir until all the batter is just moistened. It should resemble sand.
Stir in zucchini. The batter will not turn to liquid immediately, but the more you stir and mix, the batter should become more liquidy. Continue stirring until it becomes a thick, liquid batter.
Stir in 1 cup of chocolate chunks. Spread brownie batter into the prepared pan. Sprinkle remaining chocolate chunks across surface of the batter. Bake for 28-32 minutes. Toothpick insert should have a few crumbs clinging and the batter should no longer be liquid inside. Allow brownies to cool and set before cutting and serving.
This recipe works best with zucchini that is shredded right before adding it to the batter, as that is when it is the most moist.
Make sure you finely shred the zucchini. The finer shreds will disappear into the batter when baking. The zucchini will release a lot more moisture when doing finer shreds and all this moisture is needed to wet the batter.
Do not drain any of the moisture from the zucchini or pat it dry after you’re done shredding. You want to use all of that in your batter.
To make the brownies more cake-like, you can add ˝ cup more shredded zucchini. To make the brownies even more fudgy, you can reduce the zucchini by ˝ cup.