Preheat oven to 350°F. Lightly grease a 9" square pan or line pan with parchment paper.
In medium bowl, whisk together sugar, cocoa powder, espresso powder, baking powder, salt, and flour; set aside.
Combine the zucchini, melted butter, eggs, and vanilla in the work bowl of a food processor, and process until smooth.
Add dry ingredients to zucchini / egg mixture, and process briefly, just until well combined.
Add chocolate chips and pulse several times.
Pour the batter into the prepared pan.
Bake brownies for 25 to 30 minutes, until a toothpick inserted into the center comes out clean,or with a few moist crumbs clinging to it; you shouldn't see any sign of wet batter.
Remove the brownies from the oven, and allow them to cool completely before frosting.