Specifically, what is the traditional, Pennsylvania Dutch style whoopie pie filling? I live on the West Coast and never heard of these little gems until recently. I'm curious what the old-fashioned whoopie pie filling is supposed to be like. I've seen plenty of recipes involving fluff and though I love the stuff, I am having a hard time believing that these treats originated using fluff. Is the filling supposed to be like a frosting? Is it creamy, gooey, sticky or stiff?
Thanks in advance for any help!