Eggnog Thumbprints

1 . Stage

In a large bowl, cream butter and sugar until light and fluffy. Beat in egg yolks and vanilla. In another bowl, whisk flour, salt and nutmeg; gradually beat into creamed mixture. Refrigerate, covered, 1 hour or until firm enough to handle.

2 . Stage

Preheat oven to 350°. Shape dough into 1-in. balls. In a shallow bowl, whisk egg whites until foamy. Place walnuts in a separate shallow bowl. Dip balls in egg whites; roll in walnuts.

3 . Stage

Place 2 in. apart on greased baking sheets. Press a 1/2-in.-deep indentation in center of each with your thumb. Bake 10-12 minutes or until center is set. Carefully remove from pans to wire racks to cool completely.

4 . Stage

For filling, in a small bowl, beat butter and extract until creamy. Beat in confectioners’ sugar alternately with enough milk to reach spreading consistency. If desired, beat in food coloring. Fill each cookie with 1/2 teaspoon filling. Sprinkle with additional nutmeg.