Caramelizing brown sugar and butter transforms their union into a class of its own. Mix that the caramel mixture with powdered sugar (yes, more sugar) and vanilla, and you'd better make sure someone else is around to help you lick the frosting bowl. If left to lick it on your own, you will not be able stop and hence will create dangerous potential sugar coma conditions. It was necessary to pronounce aloud, "This is so good!" each time I sampled the frosting, if you can call the number of bites I took a "sample."
I had been anxiously awaiting baking this beauty since I had the privilege of tasting it while Southern Living test kitchen was perfecting it. They did get the recipe quite perfect, but the magazine fancified it with cream cheese icing and shaved coconut on the sides. I tweaked the recipe to put more spotlight on the caramel frosting that I can't stop talking about; plus, "basic" homemade layer cakes require enough labor as is.