Preheat the oven to 180°C (356°F).
Mix cake flour, cocoa powder, baking powder, and salt in a bowl.
Add cold butter and cut it into the flour mixture using your hands or a scraper until crumbly.
Add sugar and chopped chocolate chips, then mix well.
Pour in milk and egg, then bring the dough together.
Shape the dough into a circle and cut into 6 equal pieces.
Place the pieces on a baking sheet lined with parchment paper.
Bake in the preheated oven at 180°C (356°F) for 20 minutes.