1st combine butter with flour then add baking powder, sugar & Knead it well like smooth dough is formed..
Rest the dough in fridge for 30 min.
Divide the dough into 2 equal parts, in one part mix coco powder & Knead it if needed add 2tsp of milk.
Make your desired shape cookies..
Place it in baking tray & bake for 15 minute at 180.c