Heat the oven to 190 C / 375 F. Line a 12-cup muffin tin with paper liners or coat lightly with cooking spray.

Grate the zucchini on the large holes of a box grater. Transfer to a clean kitchen towel and twist firmly until no more liquid drips out. Set aside.

In a large mixing bowl, whisk together the Greek yogurt, eggs, maple syrup, and vanilla extract until smooth.

Add the squeezed zucchini to the wet mixture and stir to combine.

In a separate bowl, whisk together the whole wheat flour, protein powder, baking powder, baking soda, cinnamon, and salt until evenly distributed.

Pour the dry ingredients into the wet bowl. Fold with a rubber spatula until just combined and no dry flour is visible - stop as soon as the batter comes together.

Let the batter rest for 5 minutes. It will thicken slightly as the protein powder hydrates.

Divide the batter evenly across the 12 muffin cups, filling each about three-quarters full.

Bake at 190 C / 375 F for 20 to 22 minutes, until the tops are set and a toothpick inserted into the center comes out clean.

Cool in the tin for 5 minutes, then transfer to a wire rack and cool for at least 10 minutes before eating.