Preheat your oven to 350°F (175°C) and line a muffin tin with silicone liners or lightly grease with coconut oil.
Place the rolled oats into a high-speed blender and pulse until they reach a fine, flour-like consistency.
In a medium mixing bowl, whisk together the oat flour, vanilla protein powder, ground cinnamon, baking powder, and sea salt.
In a separate bowl, combine the Greek yogurt, egg, egg whites, maple syrup, and vanilla extract until smooth.
Gently fold the wet ingredients into the dry ingredients until just combined, being careful not to overmix.
Divide the batter evenly among 4 muffin cups, filling them nearly to the top.
Bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean and the tops are golden brown.
Let the muffins cool in the tin for 5 minutes before transferring to a wire rack to cool completely.