Step 1: Preheat the Oven

1. Preheat your oven to 350°F (175°C).
2. Grease 24 muffin cups with butter or vegetable oil, or line them with paper liners.

Step 2: Shred the Zucchini

1. Cut off the round end of the zucchini, leaving the stem as a handhold.
2. Use a box grater to shred the zucchini into a large bowl.
3. Measure out 2 cups of shredded zucchini, saving any excess for another recipe.

Step 3: Combine the Dry Ingredients

1. In a medium bowl, mix the flour, oats, sugar, cocoa powder, baking soda, salt, and optional cinnamon and chocolate chips.

Step 4: Mix the Wet Ingredients

1. In a separate large bowl, whisk the eggs and yogurt until smooth.
2. Add the shredded zucchini and stir to combine.

Step 5: Combine Wet and Dry Mixtures

1. Gradually add the dry ingredients to the wet ingredients.
2. Stir until just combined, being careful not to overmix to maintain a tender texture.

Step 6: Fill the Muffin Tins

1. Use a spoon to fill each muffin cup about three-quarters full with the batter.

Step 7: Bake the Muffins

1. Place the muffin tins in the preheated oven and bake for 20 minutes.
2. Test for doneness by inserting a toothpick or knife into the center of a muffin. If it comes out clean, they’re done. If it comes out wet, bake for an additional 5 minutes.

Step 8: Cool and Enjoy

1. Let the muffins cool in their tins for 20–30 minutes.
2. Serve warm or transfer to a wire rack to cool completely.