Preheat your oven to 350°F (175°C) and line three slots of a muffin tin with silicone liners or parchment paper.
Place the shredded zucchini in a clean kitchen towel and squeeze firmly to remove as much liquid as possible.
In a high-speed blender, pulse 0.5 cup of rolled oats until they reach a fine, flour-like consistency.
In a medium mixing bowl, whisk together the egg, Greek yogurt, vanilla extract, and maple syrup until smooth.
Fold in the oat flour, vanilla protein powder, 0.5 tsp cinnamon, baking powder, and sea salt until just combined.
Gently stir the squeezed zucchini into the batter.
In a small separate bowl, combine 1 tbsp rolled oats, 1 tsp melted coconut oil, and a pinch of cinnamon to create the streusel topping.
Divide the muffin batter evenly among the three prepared muffin cups and sprinkle the streusel mixture over the top of each.
Bake for 22-25 minutes, or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the pan for 5 minutes before transferring to a wire rack.