Preheat your oven to 350°F (175°C) and grease a loaf pan.
In a large bowl, mash the ripe bananas until smooth.
Add Greek yogurt, eggs, honey, and vanilla extract. Mix well.
In a separate bowl, combine oats, protein powder, baking soda, and salt.
Gradually add the dry ingredients to the banana mixture, stirring until just combined.
Fold in the chopped nuts if using.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 45-50 minutes, or until a toothpick inserted comes out clean.
Let the bread cool in the pan for 10 minutes before transferring to a wire rack.
Slice and enjoy your delicious protein banana bread!