Chocolate Thumbprints Cookies

Ingredients
1/2 cup(s) butter, softened
2/3 cup(s) sugar
1 egg, separated
2 Tbsp. milk
1 tsp. vanilla extract
1 cup(s) all-purpose flour
1/3 cup(s) baking cocoa
1/4 tsp. salt
1 cup(s) finely chopped walnuts
FILLING
1/2 cup(s) confectioner's sugar
1 Tbsp. butter, softened
2 tsp. milk
1/4 tsp. vanilla extract
26 milk chocolate HERSHEY'S® KISSES®
Instructions
In a large bowl, cream butter and sugar until light and fluffy. Beat in the egg yolk, milk and vanilla. Combine the flour, cocoa and salt; gradually add to creamed mixture and mix well. Cover and refrigerate for 1 hour or until easy to handle.
In a small bowl, whisk egg white until foamy. Shape dough into 1-inch balls; dip in egg white, then roll in nuts. Place on greased baking sheets. Using a wooden spoon handle, make an indentation in center of each cookie. Bake at 350°F for 10 to 12 minutes or until center is set.
For filling, combine the confectioner's sugar, butter, milk and vanilla; stir until smooth. Spoon or pipe 1/4 teaspoon into each warm cookie; gently press a chocolate KISS in the center. Carefully remove from pans to wire racks to cool.
By samsclub.com