I can't find the exact recipe, but this should help:

1 pint of heavy (whipping) cream
sugar
vanilla (or cocoa mix)

1 package of Knox gelatine (individual packet)
2 Tbs of Water

Mix water and gelatine and microwave for just under 1 minute. Set aside to cool slightly. (This is the ingredient that makes the frosting keep its shape and helps it withstand higher melting temps)

Beat whipping cream like normal adding sugar and vanilla to desired taste. When cream is near desired consistency add gelatine mixture.

***The key is to add gelatine mix before it completely cools and hardeneds.