Sift together almond flour, cake flour, and baking powder.
Cream the room-temperature butter until smooth, then add sugar and mix.
Add the egg and mix well.
Add the dry ingredients and fold gently with a spatula, cutting through the batter.
Gather the dough into a ball, wrap it in plastic wrap, and let it rest in the refrigerator for 30 minutes.
Roll out the dough to an even thickness and shape as desired.
Bake in a preheated oven at 170°C (340°F) for 15 minutes.
Cool completely on a wire rack.