Beat cold heavy whipping cream on high speed using a stand mixer or hand mixer. Beat until soft peaks form (the whipped cream has thickened slightly but does not stand up on its own). Add the marshmallow cream/fluff and vanilla and continue whipping on high speed, scraping down the sides of the mixer as needed, until a loose whipped cream forms. The end result will be stiffer than soft peaks but not all the way to a hard peak.

Use as a dip for fruit or crackers or as a topping for pancakes, pie, brownies, ice cream, or cake.