Preheat the oven to 350℉.
In a bowl, mash the bananas then whisk in egg, vanilla extract, butter and the sugar. In a separate bowl, mix the oat flour, salt and the baking powder. Combine the dry and wet ingredients.
Pour the batter in a lined loaf pan. Place the pan in the oven and bake for 45-50 minutes or until the bread is fully cooked.
Remove from the oven and allow to cool before slicing and serving, enjoy.