3 sticks unsalted sweet-cream butter, softened and cut into 1 inch pieces
1 teaspoon vanilla extract
½ cup confectioners' sugar (plus additional suger if needed)
Instructions
Spoon the marshmallow fluff into a large bowl and beat with an electric mixer on low. Gradually add the butter pieces, beating well after each addition, until smooth. Add the vanilla extract and the ½ cup confectioners' sugar. Scrape the bowl well to incorporate. Add more sugar as needed until you reach the desired texture. (I tend to use quite a bit more sugar because I like my frosting thick so it holds it's shape when I make pretty decorations on top of my cupcakes.)
Recipe by Awesome with Sprinkles at http://www.awesomewithsprinkles.com/almost-homemade-vanilla-buttercream-frosting/