Maximum make-ahead time is two hours. After that, the marshmallows start to dissolve.
1/2 cup whipping cream
1 tablespoon powdered sugar
1/2 cup miniature marshmallows
How to Make It
Beat whipping cream at medium-high speed with an electric mixer until foamy; gradually add powdered sugar, beating until soft peaks form. Fold in marshmallows. Serve immediately, or cover and chill up to 2 hours.