Heat oven to 160C.
Cream butter and icing sugar until pale yellow.
Mix in 1/2 the egg, cashew nut flour and self-raising flour.
Shape the dough into rounds of 5 to 7 g each.
Brush the top with the remaining egg.
Top with the nut.
Bake for 20 minutes or until light brown.
Keep the cookies in an air tight container.