Cream butter, 1/2 cup powdered sugar, and vanilla until well blended. Add salt and flour.
Mix in nuts until well blended. Chill dough and roll into 1 inch balls. Place on ungreased cookie sheets. Bake for 10-12 minutes. (use the nuts of your choice- black walnuts are my favorite, pecans, english walnuts and even almonds taste great!)
Remove cookies from cookie sheets and allow to cool slightly and roll in powdered sugar. Allow to cool completely and roll in powdered sugar a second time.