Jam Thumbprints

⅔ cup butter

⅓ cup white sugar

2 egg yolks

1 teaspoon vanilla extract

½ teaspoon salt

1 ½ cups all-purpose flour

2 egg whites, lightly beaten

¾ cup finely chopped walnuts

⅓ cup strawberry preserves

Preheat oven to 350 degrees F (175 degrees C). Lightly grease cookie sheets, or line with parchment paper.

In a large bowl, cream together butter and sugar until light and fluffy. Beat in egg yolks, vanilla, and salt. Gradually mix in flour.

Shape dough into 3/4 inch balls. Dip in lightly beaten egg whites, then roll in finely chopped walnuts. Place 1 inch apart on prepared cookie sheets. Press down center of each with thumb.

Bake for 15 to 17 minutes, or until golden brown. Cool on baking sheet for 5 minutes, then remove to a wire rack to cool completely. Just before serving, fill centers of cookies with strawberry preserves.