Preheat the oven to 180°C (356°F).
Cream the room-temperature butter and sugar together until smooth.
Add the egg and mix well.
Sift in cake flour, cocoa powder, baking powder, and salt.
Add chocolate chips and Bang Cookie toppings, then mix thoroughly.
Shape the dough into rounds and place them on an oven tray.
Bake in the oven at 180°C (356°F) for 12–15 minutes.