Heat the oven: Preheat to 350°F (175°C). Line a baking sheet with parchment paper or a silicone mat.
Mash the bananas: In a large bowl, mash the bananas with a fork until mostly smooth with small lumps.
Stir in the sweetener: Add maple syrup or honey. Taste the mixture; it should be pleasantly sweet but not sugary.
Add the oats: Stir in rolled oats until everything is evenly combined.
The mixture will be thick and slightly sticky.
Fold in extras (optional): Add any mix-ins like chocolate chips, nuts, or cinnamon. Don’t overload the dough; a third of a cup total is plenty.
Portion the dough: Scoop heaping tablespoons onto the baking sheet. Press each mound gently to about 1/2-inch thick; they won’t spread much.
Bake: Bake for 12–15 minutes, until the edges feel set and the bottoms are lightly golden.
Thicker cookies may need another minute or two.
Cool: Let the cookies rest on the sheet for 5 minutes, then transfer to a rack to cool completely. They firm up as they cool.