Preheat the oven to 180°C.
Mash the bananas.
In a bowl, mix the mashed banana, melted butter, sugar, and eggs together.
Sift in the cake flour, cocoa powder, baking powder, and salt, and combine well.
Add chocolate chips and mix evenly.
Pour the batter into the mold.
Bake in the oven at 180°C for 25 minutes.