Preheat your oven to 350°F and spray an 8x4” loaf pan with olive oil spray.
In a large bowl, whisk together the sugars, mashed banana, milk, oil, eggs, applesauce, and vanilla until totally combined.
In a medium bowl, whisk together the flour, oats, baking powder, baking soda, salt, and cinnamon.
Add dry ingredients to wet and use a large silicone spatula to gently mix until no flour pockets remain, being careful not to over-mix the batter.
Pour/scrape the batter into your prepared loaf pan and bake at 350°F for 70-75 minutes or until a toothpick inserted into the middle of the loaf comes out with a few crumbs. Allow loaf to cool in the pan for 10 minutes.
Use a butter knife to ease the baked bread away from the sides of the pan and then flip the loaf over onto a cooling rack (the bread should release right away). Flip the loaf right side up and allow it to cool.
Once the loaf is totally cool, you can prepare the icing.