Preheat the oven to 350°F and line a loaf pan with parchment paper or non-stick spray.
In a large bowl, combine oat flour, almond flour, protein powder, baking soda, baking powder, and salt.
In a separate bowl, whisk together Greek yogurt, maple syrup, mashed bananas, eggs, and vanilla.
Combine the wet and dry ingredients until just mixed; fold in chocolate chips or nuts if desired.
Pour the batter into the pan and bake for 55–60 minutes, until a toothpick comes out clean.
Enjoy!