Preheat the oven to 325 degrees. Generously grease the inside of a 10-inch Bundt pan with butter or a 9×13 pan, then coat with a generous amount of flour. Shake out any excess flour in the pan.
Whisk together 2 1/4 cups flour, the cocoa powder, baking soda, salt and cinnamon in a bowl.
Combine the 1/2 cup of butter and the granulated sugar in the bowl of a stand mixer. Beat on low, then medium speed, until well incorporated and creamy. Stop to scrape down the sides of the bowl. Add the eggs one at a time, then the oil and vanilla extract; beat on medium speed until well blended and smooth. Stop to scrape down the sides of the bowl.
With the mixer on low speed, alternate adding the following ingredients, beating until well incorporated after each addition: 1 cup of the flour mixture, then 1/4 cup of the espresso or strong coffee; 1 cup of the flour mixture, then 1/4 cup of the espresso or strong coffee; then the remaining flour mixture.
Stir in the zucchini and chocolate chips. Transfer the batter to the prepared pan. Bake for 50-55 minutes (bundt cake), or 35-40 minutes (9×13 pan), or until a tester inserted into the middle comes out clean.
Cool in the pan for 15 minutes; dust with confectioners’ sugar, if desired, and serve warm! (Or, with whipped cream or ice cream.)