Preheat the oven: Set your oven to 350°F (175°C).
Line a baking sheet with parchment paper for easy cleanup.
Mash the bananas: In a large bowl, mash the bananas with a fork until mostly smooth. A few small lumps are fine.
Add wet ingredients: Whisk in the egg, vanilla, and melted coconut oil or butter. Stir until combined.
Combine dry ingredients: In a separate bowl, mix the oats, flour, cinnamon, baking soda, salt, and brown sugar (if using).
This helps distribute the leavening and spices evenly.
Bring it together: Add the dry mixture to the banana mixture. Stir gently until no dry pockets remain. Fold in the chocolate chips.
Rest the dough (optional but helpful): Let the batter sit for 5–10 minutes. This allows the oats to hydrate and thickens the dough for better shaping.
Scoop the cookies: Use a heaping tablespoon or cookie scoop to drop dough onto the baking sheet, spacing about 2 inches apart.
Flatten the tops slightly with a spoon; these don’t spread much.
Bake: Bake for 10–13 minutes, until the edges look set and the tops are dry to the touch with light golden spots. Do not overbake or they’ll turn dry.
Cool: Let the cookies rest on the baking sheet for 5 minutes, then transfer to a rack to cool completely. They firm up as they cool.
Serve: Enjoy warm or at room temperature. They’re especially good with coffee, tea, or a glass of milk.