Preheat the oven to 350 degrees F, and grease or line a baking sheet with parchment paper.
Mash the banana in a medium bowl, and then stir in the remaining ingredients, ending with the oats. Make sure the ingredients are fully combined.
Scoop the batter onto the prepared sheet. I like to use a large ice cream scoop, leveling off the scoops, to get 10 evenly-shaped cookies. Flatten the cookies a bit; they will not spread while baking. If desired, sprinkle the tops with a bit of grated carrot and/or shredded coconut.
Bake for 15 minutes, give or take a minute or two depending on oven, or until the cookies are just set in the middle. Remove from the oven and allow the cookies to cool on the baking sheet for 5 minutes before removing to a rack to fully cool. (Full disclosure: I often just let them cool on the baking sheet without transferring and they turn out fine!) Once fully cool, store in an airtight container at room temperature or in the refrigerator to extend freshness. The cookies freeze well, too.