Stir up a batter for whoopie pies and you might be stirring up a little controversy, too. The Wall Street Journal reports that both Pennsylvania and Maine claim to be the origin of the dessert, and neither is yielding ground. The Portland Press Herald reported in 2011 that Maine even made the whoopie pie the state’s official treat. Between the two states there is not only a dispute about origin but also how to bake and fill the cookie sandwich. In Lancaster County, you’ll find a vanilla filling, while in Maine, marshmallow cream could be between the cookies instead.. Whoopie Pies are easy to make and very versatile, simply a pair of small sponge cakes glued together with a filling and, if desired, topping. Read More This entry was posted in Recipes , Sweet Recipes , Equipment and tagged whoopie pie , whoopie pies , dark chocolate , sponge cakes on 05/11/2010 by Patrick .. Good Housekeeping’s whoopie pie opts for the marshmallow-style filling for its chocolate cake-like cookies. It yields about 12 rich cookie sandwiches and is a wonderfully portable dessert choice..