Eggnog Thumbprints

Ingredients (16)

• 2/3 cup butter, softened
• 1/2 cup sugar
• 2 large egg yolks
• 1 teaspoon vanilla extract
• 1-1/2 cups all-purpose flour
• 1/4 teaspoon salt
• 1/8 teaspoon ground nutmeg
• 2 large egg whites
• 1 cup finely chopped walnuts
• FILLING:
• 1/4 cup butter, softened
• 1/4 teaspoon rum extract
• 1 cup confectioners' sugar
• 1 to 2 teaspoons 2% milk
• 1 to 2 drops yellow food coloring, optional
• Additional ground nutmeg