In a large bowl, mash bananas with a fork. Stir in cherries, oats, and cinnamon.
Roll tablespoon-sized rounds of dough into balls and place on a parchment paper lined baking sheet (you can put these pretty close together, they won’t rise or expand).
Bake at 350 degrees F for about 15 minutes, until golden brown.
While cookies bake, prepare icing by combining all the icing ingredients, whisk until smooth.
Allow cookies to cool slightly, then drizzle on the icing (either with a fork or by spooning icing into a baggy, cutting off the corner of the bag, and piping the frosting over the cookies).