Brown Sugar Buttercream Frosting

1. Whisk together egg, egg whites, sugar, cinnamon powder and salt in a heatproof bowl, and place in a pan of simmering water.
2. Stir continuously until the sugar has dissolved and the mixture is warm.
3. Transfer to a mixing bowl and beat on medium speed until fluffy and cooled, for about 15 minutes.
4. Beat on high speed for another 2-3 minutes.
5. Add butter(2-3 tablespoons at a time) and beat on low speed till well combined and the frosting is little stiff.

Yield: makes about 4 cups