Preheat the oven to 350F.
Grease a 9x5” loaf pan with nonstick cooking spray, add a parchment sling if you have it, and set aside.
In a medium bowl, whisk together the flour, cocoa powder, espresso powder, cinnamon, baking soda, and salt. Set aside.
In a large bowl, whisk the melted butter (I generally microwave the butter to melt right in my large glass bowl), canola oil, vanilla, brown sugar, and eggs until smooth.
Switch to a large spoon or spatula and stir the dry ingredients into the wet ingredients just until combined. Add the shredded zucchini until evenly distributed; it will look more zucchini than chocolate batter; this is right.
Stir 2/3 to 3/4 cup of the chocolate chips into the batter (depends on how many you'd like to sprinkle on top - I do 2/3 in the batter and 1/3 on top). Scoop the batter into the loaf pan and smooth out. Sprinkle the remaining chocolate chips evenly over the top of the batter. Bake 50-60 minutes, or until a skewer poked into the center of the loaf comes out without wet batter. You might see melted chocolate chips which is fine.
Remove the pan from the oven and cool on a wire cooling rack in the pan for 15 minutes. Run a thin knife around the edges of the loaf and carefully remove from the pan (this is where the sling comes in handy since you can just pull it out) and let it cool chocolate-chip side up on the cooling rack until room temperature or as long as you can wait. The longer it cools, the less likely it is to crumble. [Ask me how I know.] Slice and enjoy!