Preheat the oven to 350 °F.

Cut off the round end of the zucchini (which is a little tough), but keep the stem to use as a handhold. Shred the zucchini with a box grater, stopping when you get to the stem.

Butter or oil 24 muffing tins, or just line them with muffin cups.

Measure the dry ingredients (flour, oats, cocoa powder, sugar, cinnamon, baking soda, and salt) into a medium bowl.

Mix the zucchini, eggs, and yogurt in a larger bowl. Add the dry ingredients, then mix until everything is just combined. Add the chocolate chips if you're using them, then stir once.

With a spoon, dollop the batter into the muffin tins until each cup is 3/4 full and bake for 20 minutes.

Pull the muffins out and poke with a toothpick or knife. If it comes out wet, bake the muffins for 5 more minutes. Let the muffins cool in their tins for 20 to 30 minutes, then eat them warm!