Preheat oven to 350 degrees F. Spray a cookie sheet (line with tinfoil for easy cleanup). In a large bowl mash banana(s) (keep ratio of one banana to one cup of oats if using additional bananas). Add oats and cinnamon and mix well. Fold in you add ins of choice (there’s no quantity listed because it depends on the ripeness of your banana; add enough that you are happy, but not too much that the mixture isn’t sticky and binding to itself). Let sit for 2-3 minutes to let the oats absorb the liquid. Form into round balls, flatten into desired thickness and place on tray keeping in mind that these cookies will not expand or change shape as they bake. Sprinkle each with some extra cinnamon. Bake in preheated oven for 12 minutes. Cool before serving. These keep well for a few days in an airtight container in the fridge.