This frosting recipe is offered to go with the cake that I've called "Go-To Basic Yellow Cake". I found this icing a bit disappointing. It is amazingly easy to make and gorgeous and glossy, but the flavor is blah. But I really want this to work so I'm going to try it again with better quality cocoa (I used Hershey and someone at eG suggested El Rey). This made JUST enough for a three layer cake. It's pretty rich, so a thin layer of icing is good, but if you had any mishaps at all, you wouldn't have enough icing. It might be a good idea to make 1/4 to 1/2 again as much.
1-1/2 cups granulated sugar
1/4 cup + 2 tablespoons cornstarch; packed
7 tablespoons cocoa
1 tablespoon butter
3/4 teaspoon salt
1-1/2 cups boiling water
6 T. butter
1 T. vanilla
Recipe
Mix the first five ingredients together in a large microwave safe bowl. Whisk in the boiling water. Cook in microwave on high at 1 minute intervals stirring well after each minute with a whisk. As mixture begins to thicken cook at 30 second interval until the mixture is very thick. Then stir in the 6 T. butter and the vanilla. Stir until the butter is completely melted and incorporated. Cool before frosting cake.