Preheat oven to 350°F (175°C) and grease a 9x5 inch loaf pan.
In a large mixing bowl, mash the ripe bananas until smooth.
Whisk in the eggs, maple syrup, and vanilla extract until well combined.
In a separate bowl, mix the ground oat flour, peanut butter powder, baking soda, salt, and cinnamon.
Fold the dry ingredients into the wet ingredients until just combined.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 45 to 50 minutes, or until a toothpick inserted into the center comes out clean.
Allow the bread to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.