Preheat the oven to 350°F (175°C) and line a 12-cup muffin tin with paper liners. In a large bowl, mash the bananas, then whisk in the cottage cheese, melted butter, eggs, vanilla, and brown sugar until combined.

Sprinkle the flour, baking powder, baking soda, and salt over the wet mixture. Fold gently just until no dry streaks remain. Fold in chocolate chips or walnuts if using.

Divide the batter evenly among the muffin cups, filling each nearly to the top. Let the filled pan rest for 10 minutes if you want taller domes.

Bake for 18 to 22 minutes, until the tops are golden and a toothpick comes out clean. Cool in the pan for 5 minutes, then transfer to a wire rack. Serve warm.