They were surprisingly easy to make. Trevor was able to do quite a bit himself.
1 c. butter, softened 2 3/4 c. flour
3/4 c. sugar 1 tsp. baking soda
1 egg 1 tsp. cream of tartar
1 tsp vanilla extract 1 oz. unsweetened chocolate
Cream the butter and sugar until fluffy. Add the egg and beat well, then mix in the vanilla extract. In a separate bowl, combine the flour, baking soda, and cream of tartar. Add the flour mixture to the butter mixture, one third at a time, until thoroughly combined.
Divide the dough into two equal portions. Melt unsweetened chocolate and add to one half of the dough. Flatten each of the doughs into a disk. Cover each disk in plastic wrap and refrigerate for 2-3 hours.
Roll out chocolate and sugar doughs separately between sheets of plastic wrap into 12 x 8 inch rectangles. Remove the plastic wrap and place one rectangle on top of the first. Starting on a 12-inch side, roll up the doughs tightly, like a jelly roll. Wrap in plastic and refrigerate 1 hour.
Remove the plastic wrap and cut the roll into 1/4 inch thick slices. Bake cookies at 350 degrees for 10 minutes. Cool on cookie sheet for 3 minutes, then transfer to a wire rack to cool completely. Makes about 3 dozen.