Chop the peanuts coarsely.
Cream the butter and sugar together.
Add the egg and mix well.
Sift in the cake flour, baking powder, and salt.
Add the chopped peanuts and knead the dough.
Shape the dough into balls and place them on a baking pan.
Bake in a 180°C oven for 15 minutes.
Let the cookies cool and place them on a plate.