Mix almond flour, cake flour, and salt evenly.
Cream the butter with brown sugar and white sugar until light and fluffy.
Add the egg and mix well.
Add the flour mixture to the butter mixture and mix evenly.
Add chocolate and walnuts, then knead the dough.
Form the dough into portions and let it rest in the refrigerator.
Place the dough on a baking tray and bake.