Preheat oven to 350° Fahrenheit and line a 9x4-inch loaf pan with parchment paper.
In a large bowl, whisk together the mashed banana, non-dairy milk, maple syrup, eggs, coconut oil, and vanilla extract.
Add in the oat flour, vanilla protein powder, baking powder, and baking soda, and mix until the batter is completely smooth and combined.
Transfer the batter to your prepared loaf pan then bake the banana bread for about 40-45 minutes, or until a toothpick inserted down the center of the banana bread comes out clean. Remove the banana bread from the oven and let cool completely before slicing.