Preheat oven to 180 C (355 F) and line a mini muffin tin with paper muffin cases.
Mash banana and add peanut butter, continuing to mash until well combined.
Add coconut and cocoa powder, mix well.
Divide evenly into muffin cases.
Bake for 15 minutes.
Remove from oven and let cool for 5 minutes. They will get firmer as they cool.