Preheat the oven to 350 degrees.
In a large mixing bowl, mash the bananas with a fork. Add the nut butter and stir together with the bananas.
Next, add the oats and stir until combined.
Use a tbsp measurer, and scoop 2 tbsp of the dough into your hand. Roll the dough in your hands to form a ball. Place the ball on a baking sheet, and gently press the top with your fingers to flatten it a bit. Repeat with the rest of the dough.
Bake for 13-15 minutes, until golden brown.