Preheat the oven to 200°C.
Mix cake flour, sugar, baking powder, and salt in a bowl.
Dice cold butter and add it, mixing quickly by hand.
Add milk and egg, gently kneading into a dough.
Roll the dough to 2-3cm thickness and cut into circles or triangles.
Place on a baking tray and bake for 15-20 minutes.