Preheat the oven to 350 degrees. Grease a bread pan or place parchment in the bottom and sides of a bread pan.
Peel the bananas and add to a large mixing bowl. Mash until smooth.
Add the applesauce, maple syrup, flax egg and vanilla to the banana mash and whisk until well incorporated.
Mix the oat flour, sunflower or almond flour, baking powder, baking soda and the salt in another bowl. Add the dry mixture to the wet ingredients and whisk together until no flour patches remain.
Fold in the add-ins and pour into the prepared pan.
Bake for 60-70 minutes or until a toothpick comes out clean.
Allow to cool on a rack for 2 hours. Lift out and serve.