Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
Place the overripe bananas in a large mixing bowl and mash them until mostly smooth.
Add the honey, egg, and vanilla extract. Stir until completely combined.
Add the quick-cooking oats, cinnamon, and sea salt. Stir until the mixture is evenly combined.
Fold in the chocolate chips or your preferred mix-ins.
Use a 1-tablespoon measuring spoon or approximately 1 1/2-tablespoon cookie scoop to portion the dough onto the prepared baking sheets.
Arrange the cookies about 2 inches apart. Because these Banana Oatmeal Cookies will not spread as much as traditional cookies, gently shape or flatten the tops if desired.
Bake for 12–15 minutes, until the tops are set and the bottoms are very lightly golden.
Leave the cookies on the baking sheets for about 5 minutes.
Transfer them to a wire rack and allow them to cool completely.
Serve slightly warm or at room temperature.