You cannot lose with this frosting. It was in ms Living's April 2010 issue.
2 1/4 cup confectioners' (powdered) sugar
3/4 cup unsweetened Dutch-process cocoa powder
pinch teaspoon salt
6 ounces cream cheese, room temperature
3/4 cup (1 1/2 sticks) unsalted butter, room temperature
9 ounces bittersweet chocolate, melted (using a double boiler) and cooled
3/4 cups sour cream
Mix together confectioners' sugar, cocoa powder, and salt. In another bowl, beat together the cream cheese and butter. Mix sugar mixture into cream mixture. Mix in melted and cooled chocolate. Then mix in sour cream. (I did this without an electric mixer and it worked just fine.)
The recipe for the frosting on the web is here (it's doubled). Recipe for the cake pictured is on the web here (it's doubled and is a little different than the magazine, instead use 3/4 cup warm water and 3 Tablespoons oil).