Preheat the oven to 350 degrees. Spray a loaf pan with cooking spray. Set aside.

In a medium bowl combine the all purpose flour, whole wheat flour, baking soda, salt, and cinnamon.

In another bowl cream together the butter and brown sugar.

Add in the eggs and vanilla and mix well until combined. Stir in the applesauce.

Add the flour mixture to the butter mixture and mix until the batter starts to come together.

Mash the bananas and add them to the batter. Mix until just combined.

Pour the batter into the prepared loaf pan. Bake for one hour.

Remove from the oven and cool for 10 minutes. Remove the bread from the pan and cool completely on a wire rack.

To make the frosting beat the butter in a medium bowl with a mixer on medium speed. Add in the vanilla and mix well.

Add the powdered sugar a half cup at a time or until desired consistency is reached.

Spread the frosting over top of the bread and let rest 15 minutes before cutting.