Fudge Frosting

1. Place the chopped chocolate in a large heatproof mixing bowl.
2. In a heavy, medium-size saucepan over medium heat, combine the butter, whipping cream, and sugar. Heat until the butter is melted and sugar dissolves, stirring constantly with a rubber spatula or wooden spoon so mixture does not burn. Increase the heat to medium-high and bring the mixture to a simmer, stirring constantly. Remove pan from heat.
3. Immediately pour the hot sugar mixture over the chocolate. Let stand for about 2 minutes, and then stir until smooth. Stir in the vanilla. Set aside to cool for about 30 minutes.
4. Set the bowl of frosting in a larger bowl of ice water. Using an electric hand mixer beat the frosting on medium speed until it thickens and turns lighter in color. This may take from 15 to 20 minutes. The frosting is ready when it no longer drips of the beaters when they are lifted; don’t over-beat or the frosting will turn grainy.
5. Using an offset spatula, spread frosting between layers and over top and sides of cake.

source:allrecipes.com