Preheat your oven to 350°F (175°C).
Mash the ripe bananas in a mixing bowl until smooth.
Combine the mashed bananas with rolled oats, honey or maple syrup, eggs, baking powder, and vanilla extract. Stir until well combined.
Grease an 8×8-inch baking dish or line it with parchment paper.
Pour the banana-oat mixture into the prepared baking dish and spread it evenly.
Bake for about 25-30 minutes until golden brown and a toothpick inserted in the center comes out clean.
Let the bars cool for at least ten minutes before slicing into squares.
