Preheat the oven to 180°C (356°F).
Cream the butter and sugar together until smooth.
Add the egg and mix again.
Sift in the flour, cocoa powder, and baking powder, then mix.
Add the chocolate chips and evenly fold them into the dough.
Scoop the dough into balls and place them on a baking tray.
Bake in the oven at 180°C (356°F) for 12 minutes.