Chocolate Thumbprint Cookies 2 Recipe

Cream butter, sugar, egg yolk, milk and vanilla in small mixer bowl. Combine flour, cocoa and salt; blend into creamed mixture. Chill dough about 1 hour or until firm enough to handle. Prepare Vanilla Filling by combining all ingredients together. Roll dough into 1 inch balls. Roll in sugar. Place on lightly greased cookie sheet. Press thumb gently into center of each cookie. Bake at 350° for 10 - 12 minutes until set. As soon as cookies are removed from oven, spoon about 1/4 teaspoon filling into "thumbprint". Gently place Hershey Kiss in center of each cookie. Carefully remove cookies from cookie sheet; cool on wire rack.