Melt chocolate in a bowl set over a saucepan of simmering water. Let cool slightly. Beat together butter, sugar, and salt with a mixer until pale and fluffy, about 5 minutes. Gradually beat in chocolate, then sour cream, and beat until thoroughly incorporated. Frosting should be spreadable. If too loose, refrigerate, stirring occasionally, until thickened. Use immediately, or transfer to an airtight container and refrigerate up to 3 days. Before using, bring to room temperature, and beat until smooth.
This was the best icing recipe I have tried. I highly recommend it! This on the chocolate flecked layer cake made it almost taste like a scor bar. Delicious.
This recipe worked perfectly for me with the cake. The entire recipe was wonderful.
I was surprised that this turned out, but somehow with so little sugar and so much butter the frosting is thick, shiny, and delicious - it's flavor is subtle, similar to a butter-cream without all the work and with a slight tang from the sour cream. My only advice would be to make sure your chocolate is sufficiently cooled, and be aware that it hardens considerably in the fridge so leave time to bring to room temperature if you're not assembling the cake immediately.
I followed the recipe to a t and it turned out great! I will definitely make it again.
I used this frosting with the chocolate-flecked cake and was very disappointed. I think there must be a mis-print. Four sticks of butter with only 1 cup of confectioner's sugar? Add sour cream and melted chocolate and it was chocolate soup. Chilling did not help, whipping for 20 minutes did not help. Added more confectioner's sugar and it was sickening sweet. Very expensive for the result. Fail.