A whoopie pie is another sweet treat that owes its heritage to the Amish. Common in New England, the popular "sandwich" pie is made from two cookie-shaped cakes, with a white, fluffy filling, usually made from marshmallows. The most traditional and common flavor of a whoopie pie is chocolate, but pumpkin whoopies are popular in the autumn. The whoopie pie migration from Lancaster County, Pennsylvania, is most likely due to the inclusion of the recipe in a 1930s New England cookbook. Marshmallow Fluff was also a popular grocery store product in the New England area in the 1920s and 30s.