Preheat the oven to 350°F. Grease a 4x8-inch loaf pan with cooking spray or butter.
Mix all the dry ingredients - whole wheat flour, sugar, baking soda, and salt till they are combined. Set aside.
In a mixing bowl, add coconut oil, yogurt, vanilla extract, and egg and mix them well.
Mix the dry ingredients with the wet till they are combined. Do not overmix. Note: The batter will not be runny, it will be moist and thick.
Add grated zucchini and mix it in.
Add about 1/4 cup of chocolate chips and stir it in.
Pour the batter into the greased pan and sprinkle the remaining chocolate chips on top.
Bake for 50 - 60 minutes until a toothpick inserted in the center comes out clean. (I checked at the 50-minute mark and the zucchini bread was done)
Remove the loaf from the oven and let the zucchini bread cool in the loaf pan for about 10 minutes.
Run a butter knife through the edges to loosen it. Transfer to a wire cooling rack and allow time to cool completely.
Use a serrated knife to cut the bread into slices.
Notes
Don't forget to squeeze the water from zucchini - You should squeeze out the excess water from zucchini if it has a lot of liquid in it. Typically, if you use a large-hole grater, it doesn't ooze out much and you can skip this step.
Zucchini - I usually grate one whole zucchini and depending on the size it will yield about 1 - 1.5 cups in the recipe. Don't use more than 1.5 cups in this recipe or else the bread won't rise as much.
Baking soda reacts well with cocoa powder and yogurt to provide the necessary lift needed for this bread. Make sure to bake the batter immediately after it is ready.
Should you add baking powder? I have tested with and without using baking powder in this recipe. It does give the bread a slightly better rise but not significant enough so I chose to not use it. But if you want to, reduce the baking soda in the recipe to 3/4 teaspoon and use 1/4 teaspoon baking powder.
Using coconut oil - If you are using coconut oil in this recipe, remember the following instructions -
Use it in liquid form. If you have to heat it, allow it to cool briefly before mixing it with eggs to prevent it from cooking.
Also, use eggs at room temperature otherwise the coconut oil will solidify.
To make zucchini bread without chocolate, skip the cocoa powder and increase the amount of whole wheat flour by 1/2 cup.
For chocolatezucchini muffins, grease the muffin tin and pour the batter in each of the molds till it is 3/4th full. Bake for about 35 minutes at 350°F.
Storage instructions - I usually refrigerate the leftovers. I sometimes make a double batch and freeze one. To freeze, chop them into slices and put them in a freezer-safe Ziploc bag. Before serving, microwave them for 10-15 seconds and enjoy it warm.