Combine cake flour, baking powder, sugar, and salt in a bowl.
Add cold butter and rub it in with your hands until the mixture is crumbly and well blended.
Add milk and egg, then form the dough.
Flatten the dough and cut into triangles or circles.
Place on a baking tray and bake in a preheated oven at 180°C (356°F) for 20 minutes.