1Heat oven to 350 degrees.
In large mixing bowl, combine 1c sugar, butter and vanilla.
Beat at medium speed until light and fluffy.
Add flour and salt.
Beat at low speed until soft dough forms.
Stir in walnuts
2Shape dough into 1-inch balls.
Roll balls in granulated sugar.
Place balls 2 inches apart on ungreased cookie sheet.
Flatten balls with fork in crisscross pattern.
Bake 12 to 15 minutes or until edges are lightly golden brown.
3In medium mixing bowl, combine filling for ingredients. Beat at low speed until smooth.
Spread about 2 teaspoons filling on bottoms of half the cookies.
Gently press bottoms of remaining cookies against filling to form sandwiches.