Preheat the oven to 350°F (175°C) and lightly grease an 8x8-inch baking dish.
Place the cottage cheese, mashed bananas, eggs, milk, maple syrup, and vanilla extract into a blender. Process until the mixture is completely smooth and homogeneous.
In a large mixing bowl, combine the rolled oats, ground cinnamon, baking powder, and salt.
Pour the blended liquid mixture over the dry oat mixture and stir with a spatula until thoroughly combined. Fold in walnuts or blueberries if desired.
Transfer the batter into the prepared baking dish, spreading it into an even layer.
Bake for 30 to 35 minutes, or until the center is set and the edges are lightly golden brown.
Allow the bake to cool in the pan for at least 10 minutes to firm up before slicing into 6 portions.