Preheat the oven to 350°F (175°C) and line a 12-cup muffin tin with paper liners or grease it lightly.
In a large mixing bowl, mash the ripe bananas until smooth.
Add the eggs, Greek yogurt, honey, and vanilla extract to the mashed bananas and whisk together until well combined.
In a separate bowl, combine the rolled oats, vanilla whey protein powder, baking powder, baking soda, ground cinnamon, and salt. Stir to evenly distribute the ingredients.
Gradually add the dry ingredients to the wet ingredients and gently fold together until just combined. Do not overmix.
Divide the batter evenly among the 12 muffin cups, filling each about 3/4 full.
Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Remove the muffins from the oven and allow them to cool in the tin for 5 minutes before transferring to a wire rack to cool completely.
Serve warm or at room temperature.