This Chocolate Zucchini Bundt Cake is insanely moist, so fudgy, and loaded with chocolate flavor! No one will even know there's 2 whole cups of shredded zucchini hiding inside! Delicious with chocolate glaze, but can easily be served with whipped cream or a dusting of powdered sugar instead!
Position a rack in the center of the oven. Preheat oven to 325 degrees (F).
Generously grease a 10-cup Bundt Cake pan with non-stick baking spray. Set aside.
In a large bowl, sift together the flour, cocoa powder, baking soda, baking powder, salt, cinnamon, and espresso powder. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a handheld electric mixer, beat the butter until smooth and creamy, about 1 minute. Gradually add in the sugars and beat on medium-high speed until well combined, about 2 minutes. Stop the mixer and scrape down the sides and bottom of the bowl, then beat for another 30 seconds. Beat in the vanilla.
Add in the eggs and egg yolks, one at time, beating well after each addition and scraping down the sides and bottom of the bowl as needed.
On low speed, add in the flour mixture in three additions, alternating with the sour cream in two additions, beginning and ending with the flour. Mix until just combined!
Using a rubber spatula, fold in the zucchini and chocolate chips, mixing just until combined. Then scrape the batter into the prepared pan and smooth the top with a spatula.
Bake for 65 to 70 minutes, or until a cake tester inserted in the center comes out clean.
Cool in the cake pan, on a wire rack, for 20 minutes. Unmold the cake onto the cooling rack, turn the cake right side up, and cool completely.
For the Espresso Chocolate Glaze:
Finely chop the chocolate and place it in a small heatproof bowl. Set aside.
Warm the cream over medium heat until it comes to a boil. Add in the espresso powder and whisk smooth.
Pour the cream over the chopped chocolate and let it sit for 1 minute, then whisk smooth. Whisk in the vanilla, if using.
Slowly pour the glaze over the cake, letting it drip down the sides. Then sprinkle with mini chocolate chips.
Allow the glaze to set for 20 minutes before slicing and serving!
Store in an airtight container for up to 3 days, or in the fridge for up to 5 days.