Preheat oven to 350 degrees. Line a muffin pan with silicone baking cups or paper liners. Set prepared pan aside.
In a large mixing bowl, combine the dry ingredients; oat flour, protein powder, sweetener, baking powder and salt. Whisk together to combine. Set aside.
In a smaller mixing bowl, combine the wet ingredients; mashed bananas, milk, Greek yogurt, vanilla and egg. Whisk together well. Pour into the dry ingredients. Using a rubber scraper, mix the wet and dry ingredients together until smooth. Batter will be slightly thick.
Fold the blueberries gently into the batter using a rubber scraper.
Using a ladle or large ice cream scoop, fill each muffin cup nearly full. Optional; top each muffin with additional oats and/or fresh blueberries.
Bake muffins at 350 degrees for 30-32 minutes or until toothpick inserted into a muffin comes out clean and crumb-free. Remove from oven and let cool before serving. Enjoy right away or wrap and freeze for later.