chocolate fudge frosting

[smartie]

need a recipe for homemade choccy fudge frosting that comes out fluffy (similar to the Betty Crocker/Duncan Hines type) which can be spread on and doesnt harden into a rock when the cake is put into the fridge. Needs to be very dark and chocolatey.

I can make buttercream frosting with no problem but that is not what I am looking for.

thanks