2 teaspoons very hot water
rounded 1/4 teaspoon salt
2 cups marshmallow creme (1 7-ounce jar)
1/2 cup shortening
1/3 cup powdered sugar
1/2 teaspoon vanilla
Combine the salt with the hot water in a small bowl and stir until salt is dissolved. Let this mixture cool.
Combine the marshmallow creme, shortening, powdered sugar, and vanilla in a medium bowl and mix well with an electric mixer on high speed until fluffy.
Add the salt solution to the filling mixture and combine.
Makes 1 1/2 cups.