Preheat the oven to 350°F (175°C).
Line an 8x8 inch baking pan with parchment paper.
In a large bowl, mash the ripe bananas well. Add almond milk, honey or maple syrup, and vanilla extract. Stir until well combined.
In another bowl, mix rolled oats, baking powder, cinnamon, and a pinch of salt.
Gradually mix the dry ingredients into the wet mixture until fully incorporated. If using mix-ins, fold them in gently.
Pour the batter into the prepared pan and spread evenly.
Bake for about 20-25 minutes, or until a toothpick inserted comes out clean.
Let them cool for a few minutes before lifting them out of the pan using the parchment paper. Slice into bars and enjoy!
