Preheat the oven to 180°C (356°F).
Mix butter and brown sugar until smooth.
Add egg and mix thoroughly.
Sift cake flour, cocoa powder, and baking powder into the mixture.
Add chocolate chips and Rabang cookie nuts, then knead the dough.
Shape the dough into balls and place them on a baking pan.
Bake in the preheated oven for 12–15 minutes.
Cool on a wire rack.