Preheat the oven to 350 degrees Fahrenheit.
Add 1 1/2 cups mashed ripe bananas, 1/2 cup creamy almond butter, 1/4 cup pure maple syrup, and 1 teaspoon vanilla extract to a bowl, then mix well.
Add 1 3/4 cups oat flour, 1 tablespoon baking powder, 1/2 teaspoon ground cinnamon, and 1/4 teaspoon salt to a second bowl, then mix well.
Transfer the dry ingredients to the bowl with the wet ingredients, then mix to combine.
Add any optional ingredients such as dark chocolate chips or chopped walnuts, then mix to combine.
Transfer the batter to a 9-inch loaf pan lined with parchment paper, then spread in an even layer.
Bake for 50 minutes or until a toothpick inserted into the center of the bread comes out looking clean.
Let cool completely before removing from the pan and serving.