Here's an excerpt from Cooking by James Peterson:
Here's a great YouTube video of a recipe from CakeLove.com:
1 cup sugarI've seen a lot of posts where people have trouble keeping this kind of icing stabilized. I'm a little concerned about trying it since it's August in Texas. Apparently heat and IMBC are natural enemies.
1/4 cup water
Bring to a boil until 245 degrees.
5 egg whites
Beat low until frothy, then beat high. Add 2 oz. sugar when egg whites form stiff peaks.
Add syrup slowly.
Add 16 oz. butter.
Here's another recipe from www.make-fabulous-cakes.com: