Add together the dry ingredients, the flour, sugar, cocoa powder, baking powder, baking soda, and salt, and whisk them together. 2 cups all purpose flour, 1 cup granulated sugar, 1/2 cup unsweetened cocoa powder, 2 tsp baking powder, 1/2 tsp baking soda, 1/2 tsp salt
In another bowl, combine the eggs, buttermilk, vegetable oil, and vanilla extract. Stir to combine well. 2 large eggs, 1 cup buttermilk, 1/2 cup vegetable oil, 1 tsp vanilla extract
Slowly mix the dry ingredients into the wet ingredients until just combined. A few small lumps are okay.
Add the grated zucchini and 1 cup of the chocolate chips, and fold them into the batter. 1 cup zucchini, 1 1/2 cups semi-sweet chocolate chips
Cover the batter and let it rest for 15 minutes.
Preheat the oven to 425 degrees Fahrenheit. Line a muffin pan with muffin liners, in every other spot.
Scoop the batter into the muffin tins, filling them just to the top.
Sprinkle the remaining chocolate chips over the top of the muffins. Sprinkle with coarse sugar if desired.
Bake the muffins for 5 minutes in the preheated oven. Then lower the temperature to 350 degrees F. (Do not open the oven, keep the muffins in the oven). Bake for another 10 to 15 minutes, or until a toothpick can be inserted in the center and comes out clean.
Remove the muffins from the oven and let them cool in the pan for about 10 minutes. Then carefully remove them from the pan, and enjoy, or let tem continue cooling.
Repeat with baking additional muffins, preheating the oven back to 425 F between.
Store any leftovers in airtight container