Preheat your oven to 350°F (175°C) and lightly grease a standard muffin tin with avocado oil or coconut oil spray.
Place the rolled oats into a high-speed blender and pulse until they reach a fine, flour-like consistency.
Add the banana, liquid egg whites, Greek yogurt, baking powder, cinnamon, sea salt, and vanilla extract to the blender with the oat flour.
Blend on medium-high until the batter is completely smooth and well-combined.
Divide the batter evenly among 6 muffin cups, filling each nearly to the top.
Bake for 22 to 25 minutes, or until the tops are golden and a toothpick inserted into the center comes out clean.
Remove from the oven and allow the muffins to cool in the pan for at least 5 minutes before transferring to a wire rack.