Growing up in New England, whoopie pies were traditional Fourth of July fare and I've got some time on my hands and want to make my own. The problem? I live in the South and Marshmallow Fluff is impossible to find. The Marshmallow Fluff recipe (ssh, it's my grandmother's secret... don't tell!) calls for a 2:2:1 ratio of Fluff:confectioner's sugar:butter. Is there a substitution (marshmallow cream?) I can make for the Fluff that will keep it nice and, well, fluffy?