Heat the oven: Preheat to 350°F (175°C). Line a baking sheet with parchment paper to prevent sticking.
Mash the bananas: In a large bowl, mash the bananas until mostly smooth with a few small lumps.
Stir in wet ingredients: Add the maple syrup, almond butter, and vanilla.
Whisk or stir until the mixture looks creamy and well combined.
Add dry ingredients: Sprinkle in the oats, cinnamon, baking powder, and salt. Stir until everything is evenly coated and the batter holds together.
Fold in extras: If using nuts, dried fruit, or chocolate chips, gently mix them in now.
Portion the cookies: Scoop heaping tablespoons (about 2 tablespoons each) onto the lined baking sheet. Use damp fingers to flatten and round each mound to about 1/2 inch thick.
These won’t spread much in the oven.
Bake: Bake for 13–16 minutes, until the edges feel set and the bottoms are lightly golden.
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.