Beat butter at medium speed with an electric mixer until creamy; gradually add powdered sugar, beating well. Add milk and liqueur, beating until blended.
Shape sugar mixture around cherries, coating completely, and place on wax paper.
Microwave chocolate squares and shortening in a 2-cup glass measuring cup at HIGH 1 1/2 minutes or until melted, stirring twice.
Dip coated cherries by stems into chocolate mixture, allowing excess to drip; place on wax paper. Let stand until firm. Store loosely covered in a cool place 1 week or until centers soften.