Preheat the oven to 180°C
Soften the butter at room temperature
Mix protein powder, cake flour, almond flour, baking powder, and salt together
Add sugar and egg to the butter and whisk until combined
Add the dry mixture to the butter mixture and fold with a spatula
Add dark chocolate chips to complete the dough
Shape the dough into balls and place on a baking tray
Bake in the oven for 12-15 minutes