Devil's Food Cake

We had friends for lunch on Sunday, and I was asked by their son if I would make the Sachertorte, as they had tasted it previously and like it. Unfortunately at this stage I am compelled not to repeat anything!! Thankfully, I had one more chocolate recipe in the book that I had not made - Devil's Food cake, and this went down really well!
I was not quite sure what to expect with this. Apologies for not taking a photo of the inside. The sandwich cake was very dark in colour, with almost a reddish brown tinge. It was very moist and tasty. The only problem I faced was with the frosting. Having had a disaster with it on my walnut cake, I thought I would be ok this time. I whisked it for 12 minutes over hot water, and this time it seemed firmer than before. I expected it to set, as apparently "it sets rapidly". I put it in a cool place (the conservatory), not the fridge, but to no avail. Once again, the icing did not set. Thankfully, it did taste  better than on the walnut cake, but I couldn't help feel that it was not right.
I would make the sponge again, as it was really nice, and only used store cupboard ingredients, however, I think I would either sandwich it with cream, or chocolate icing. I dont think I will be making frosting again in a hurry. We gave it 8.0, but it could easily get higher with a change of filling. The main thing was that the guests enjoyed it!