Prepare the almonds and butter at room temperature.
Whip the butter and sugar together until soft and creamy.
Add the egg and mix well.
Sift in cake flour, almond flour, and baking powder, and combine.
Add sliced almonds and finish the dough.
Shape the dough into cookies and place them on a baking tray.
Bake in the oven at 180°C for 15 minutes.
Cool on a wire rack.