Preheat oven to 350°F and line a muffin tin with silicone liners.
Place shredded zucchini in a clean kitchen towel and squeeze out as much moisture as possible to ensure a firm texture.
In a large bowl, whisk together the Greek yogurt, egg whites, maple syrup, and vanilla extract until completely smooth.
Stir the squeezed zucchini into the wet mixture until evenly distributed.
In a separate bowl, sift together the oat flour, protein powder, cinnamon, nutmeg, baking powder, and sea salt.
Fold the dry ingredients into the wet ingredients using a spatula until just combined, being careful not to overmix.
Divide the batter evenly among 6 muffin cups, filling each nearly to the top.
Bake for 22-25 minutes or until the tops are golden and a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.