Preheat oven to 350 degrees.
Mash up bananas in a small bowl with a fork.
Add in the rolled oats to the mashed bananas and mix together until fully incorporated.
Mix in the additional add-in(s).
Scoop with a spoon and drop a small ball of dough onto the tray.
Bake on a greased cookie sheet (or lined with parchment paper) for 13-15 minutes and slightly golden on top.
Makes about 14-15 cookies.
Store in an airtight container. Can be kept at room temperature for up to 3 days, in the refrigerator for up to 1 week, or in the freezer to up to 3 months.
