Combine sugar and butter in bowl. Beat at medium speed, scraping bowl often, until creamy. Add egg, milk and 1/2 teaspoon peppermint extract; continue beating until well mixed. Add melted chocolate; continue beating until well mixed. Add flour, baking powder and salt; beat at low speed until well mixed.
Divide dough in half; shape each half into 8x2-inch long log. Wrap each log in waxed paper or plastic food wrap. Refrigerate 4 hours or overnight.
Heat oven to 350°F.
Cut logs into 1/4-inch slices with sharp knife. Place 1 inch apart onto ungreased cookie sheets. Bake 10-12 minutes or until set. Cool 1 minute on cookie sheet; remove to cooling rack. Cool completely.
Melt candy coating in 1-quart saucepan over low heat, stirring occasionally, 8-12 minutes or until smooth. Remove from heat. Stir in 1/2 teaspoon peppermint extract and food color. Tipping saucepan slightly, dip cookies
into melted coating. Lightly shake off excess coating. Place onto waxed paper. Let stand until coating is firm.
Melt 12 ounces semi-sweet baking chocolate and shortening in 1-quart saucepan over low heat, stirring occasionally, 6-8 minutes or until smooth. Remove from heat. Tipping saucepan slightly, dip cookies into melted chocolate, overlapping
of green coating. Lightly shake off excess chocolate. Place onto waxed paper.
Let stand at least 2 hours or until coating is firm. Store in single layer between sheets of waxed paper in loosely covered container in cool place.