Preheat the oven to 350ºF. Line a loaf pan with parchment paper and set aside.
Add the dry ingredients to the bowl and whisk to combine.
In a separate bowl, beat together the eggs, banana, syrup, oil and vinegar. Pour wet ingredients into dry and stir together until a thick batter has formed.
Shred the zucchini and press the juices out using a clean dish towel. Add zucchini and chocolate chips into the batter and fold together.
Transfer batter to the prepared loaf tin, sprinkle with additional chocolate chips and shredded zucchini if desired. Bake on the center rack for 45 - 55 minutes (mine took around 48) until the top has turned golden brown and a cake tester inserted into the center comes out clean.
Cool in the pan for 1 hour then transfer to a wire rack and cool completely before slicing. It's important the loaf has completely cooled or else it might be soggy in the center!