Alton Brown Fail.
I made some red velvet cupcakes this weekend, and was experimenting with new kinds of frosting. I'd had good success with cream cheese frostings previously, but I wanted something that was a little more stable.
I tried Alton Brown's Buttercream from "The Icing Mam Cometh". Alas, it was an epic fail - I ended up with a custard-looking soup instead of frosting. I then turned the mixer onto high for 10 minutes, and then I got a sweet creamed butter. Not a great result, since I started with butter and sugar.
I did use egg substitute instead of the 4 eggs; since they would have been raw in the final frosting. That should have been fine since Brown has approved that substitution for other frosting recipes. I think that one trouble point was the "whip the eggs until light and fluffy" instruction. I suspect that "whip the hell out of the eggs until stiff peaks form" is more appropriate. My work bowl also got a bit warm to touch when I added the hot sugar, so that might have broken the frosting structure.
In the end I bagged the failed frosting, and made the simple white frosting that's included with the red velvet recipe. It was a little thick, but at least the cupcakes aren't naked.