Preheat the oven to 350℉ and line or spray a 9x5 loaf pan.
In a medium size mixing bowl, add the flour, cocoa powder, baking powder, baking soda, ground espresso and salt. Whisk to combine and set aside.
Finely grate your zucchini onto a clean tea towel or a couple of paper towels. Squeeze the excess juice into a large mixing bowl. Then add in the shredded zucchini.
Then in the large mixing bowl, add the eggs and brown sugar. Whisk until well combined. Add in the oil, milk, Greek yogurt and vanilla extract. Whisk until well combined.
Add the dry mixture into the wet mixture and using a spatula, fold together gently until half combined. Add in the chocolate chips and fold together until just combined.
Pour the batter into the prepared loaf pan. If you want that traditional looking crack in the middle once baked, run your spatula lengthwise down the middle of the batter making a line in the batter. Bake for 45-50 minutes or until the top springs back when touched and a toothpick comes out clean.
Allow to cool in the pan for 10 minutes before transferring to a wire rack to completely cool. Store in an airtight container for up to 3 days or freeze for up to 3 months and enjoy!