Ingredients
6
egg whites
1 1/2
cups sugar
1 1/2
cups butter, softened and cut into 1-inch pieces
2
teaspoons vanilla
2
oz semisweet or bittersweet baking chocolate, chopped (from 4-oz bar)
Preparation
In medium glass or metal bowl, beat egg whites and sugar with whisk until blended. Set over pan of simmering water, beating occasionally, until sugar has dissolved and egg mixture reaches 160°F on candy thermometer, 16 to 20 minutes. Remove from heat.
Pour into bowl of electric stand mixer fitted with whisk attachment. Beat on high speed 2 to 3 minutes or until glossy peaks form and bowl has cooled to feel slightly warm. Still on high speed, slowly add 1 1/2 cups softened butter, one piece at a time, scraping side of bowl occasionally, until mixture is smooth, thick and shiny, 12 to 14 minutes. Beat in vanilla. If mixture separates, beat until smooth.
In small microwavable bowl, microwave chopped chocolate uncovered on High 60 seconds, stirring halfway through microwave time. Continue to microwave in 10-second increments, until chocolate can be stirred smooth. Let stand 10 minutes. Beat cooled melted chocolate into frosting until smooth.
Fill and frost 1 (8-inch) three-layer cake.
