Preheat oven to 350°F / 177°C. Grease 1 9x5inch / 23x13cm bread pan or line with parchment paper.
In a large bowl, beat together sugar, oil, yogurt, egg, vanilla, and sourdough discard if using. Stir in zucchini.
In a separate bowl, whisk together flour, cocoa, baking soda, salt, and baking powder.
Fold dry ingredients and chocolate chips into wet ingredients until just combined. Reserve a handful of chocolate chips for sprinkling on top, if you wish.
Pour into the prepared bread pan, sprinkle with remaining chocolate chips, and bake in preheated oven for 40-45 minutes or until a toothpick inserted in the center comes out mostly clean. A few moist crumbs clinging to the toothpick is a good sign the bread is done but still moist! Allow to bread to cool before removing it from the pan and serving.
Other Info (pictures, nutrition, etc)
If you desire a sweeter bread, you can up the sugar to 1 cup / 200g.
I know not everyone has plain yogurt on hand, so if you have French Vanilla or another flavor you wouldn’t mind mixing with chocolate, use that! Flavored yogurt has added sugar, so if that is important to you to keep the sugar down, simply reduce the sugar from 1/2 cup / 100g to a scant 1/2 cup / 80-90g.
Zucchini quantity can be played with! My mom’s original recipe calls for 1 cup, but here I’ve increased it to 1 1/2 cups. If you can’t detect the veggies, why not add more so you get maximum nutrition? On that note, measuring grated, sliced, or cubed veggies by weight is always a bit tricky. From my research, the average medium zucchini weighs about 5oz or 140g, so if you’re buying zucchini specifically for this recipe, you’ll probably want to get 2, making a bit more than 1 1/2 cups, but that’s ok! I would use it all. Or just get one zucchini that’s a bit bigger. However you please, as I said it’s flexible! And I just way over-analyzed that for you. You’re welcome.