Preheat oven to 375 degrees F.
In a large bowl, mash the ripe bananas. Add the vanilla, almond milk, almond butter, and maple syrup. Whisk until well combined.
Add the oats, ground flaxseed, cinnamon, baking powder, and salt. Stir with a spatula until combined. Fold in the blueberries.
Pour batter into a 9×9 square baking pan (8×8 works too, but you may have to bake it longer). Top with additional blueberries, if desired. Bake for 30-35 minutes, or until middle is set and lightly golden brown. Let it cool for 10 minutes and serve warm. If you want it to be more firm and more like bars, let it cool completely before slicing. Enjoy!
Store leftovers in an airtight container in the fridge. Reheat in the microwave with a splash of milk or enjoy cold if you like it more firm.