Be careful not to overbake these pecan-loaded treats: they are best when nice and chewy. Begin to check for doneness after about 5 minutes.
Melting Chocolate in Bag
Place both chocolate and shortening in a heavy-duty plastic bag and push all to one corner. Tie the bag just above this mixture, then set the bag in a bowl of warm water to melt. Rub to blend the contents.
Invert the bag so the tip faces upward. Squeeze a little of the melted mixture away from the tip, then snip off a tiny piece from the corner to create an opening.
Squeeze the bag gently to pipe out the chocolate in a steady stream. Move back and forth across the cookies, set on a wire rack, to create a network of lines.