Yield: Makes about 50
Beat butter and shortening in a mixing bowl with an electric mixer on medium to high speed for 30 seconds. Add sugar, baking soda and salt; beat until combined, scraping sides of bowl occasionally. Beat in egg, milk and vanilla until combined. Beat in as much of the flour as you can with the mixer. Stir in remaining flour with a wooden spoon.
Divide dough in half. Into one portion, stir melted chocolate and nuts. Into the other portion, mix green food coloring until well-combined; stir in miniature chocolate pieces. Divide each portion of dough in half.
To shape dough, line the bottom and sides of a 9-by 5-by 3-inch loaf pan with clear plastic wrap. Press 1/2 of chocolate dough evenly in the bottom of the pan atop the plastic wrap. Top with half the green dough, then the remaining chocolate dough, then the remaining green dough.
Invert pan to remove dough. Peel off plastic wrap. Cut dough crosswise into thirds. Wrap each portion in plastic wrap; chill in freezer until very firm. Unwrap each third and slice crosswise into 1/4-inch-thick slices. Place slices 2-inches apart on ungreased cookie sheet.
Bake in a 375-degree oven about 10 minutes or until edges are firm and bottoms are lightly browned. Transfer to wire racks and cool. Makes about 50.
Source: Better Homes and Gardens Christmas Cookies magazine, 2000
Please note that some ingredients and brands may not be available in every store.