Preheat the oven: Preheat to 350°F and line a baking sheet with parchment paper for easy cleanup.
Mash the bananas: Add ripe bananas to a large bowl and mash with a fork until mostly smooth.
Add wet ingredients: Stir in the egg or flax egg, vanilla, and maple syrup or honey if using. Add nut butter or coconut oil for a richer texture.
Mix in the oats: Add oats, cinnamon, and salt. Stir well, then let the batter rest for 5 minutes so the oats can absorb moisture.
Fold in mix-ins: Stir in chocolate chips, nuts, raisins, or your favorite add-ins. Keep mix-ins moderate so the cookies hold together.
Scoop and shape: Scoop the dough onto the baking sheet, leaving space between each cookie. Gently flatten each one before baking.
Bake: Bake for 12–15 minutes, until the tops look set and the edges are lightly golden. Avoid overbaking.
Cool: Let the cookies cool on the pan for 5 minutes, then transfer to a wire rack to firm up completely.
