Preheat the oven to 180°C.
In a bowl, mix cake flour, baking powder, sugar, and salt.
Add cold butter and mix with your hands until crumbly, like streusel.
Combine milk and egg, then add to the dough and mix lightly.
Add cocoa powder and chocolate chips, and mix well.
Gather and flatten the dough, then cut into desired sizes.
Place on a baking sheet lined with parchment paper.
Bake in the preheated oven for 20 minutes.