The big change in this recipe is the substitution of butter for shortening. Since this isn’t a standard buttercream recipe – because of the addition of Marshmallow Fluff – the structure of the filling doesn’t necessarily need to be reinforced with shortening. Butter will also help make the filling a bit more rich and creamy, as is the nature of butter. So if you would like to give this version of whoopie pie filling a go, keep reading for the rest of the ingredients, measurements and instructions; if not, we still highly recommend our initial filling recipe.
What You’ll Need:
- 1/2 cup unsalted butter, softened
- 1¼ cups confectioners sugar
- 2 cups Marshmallow Fluff
- 1½ teaspoons pure vanilla extract
- Whoopie Pie cakes, cooled completely
- In a medium bowl, beat butter, sugar, and Marshmallow Fluff. Stir in vanilla extract until well blended.
- Spread the flat side of one Whoopie Pie cake with a generous amount of filling. Top with another cake, then repeat until all are filled.