Gesine's Swiss Buttercream

Ingredients:
10 egg whites
2 cups sugar
1 1/2 to 2 pounds butter (6 to 8 sticks) butter, slightly colder than room temperature and cut into 1/2 inch cubes

Preparing the buttercream:
Simmer water in a sauce pan. Place egg whites and sugar in a metal mixing bowl (i.e. your KitchenAid mixing bowl). Get a candy thermometer handy. Whisk the egg whites and sugar CONSTANTLY until the sugar is melted and the concoction reaches 160 degrees F, but do not let the eggs cook and curdle -- Whisk constantly.

Transfer immediately to your mixer and whip on high until the meringue has doubled or tripled in volume, is white and shiny, holds a peak, and is cool to the touch.

With your mixer on medium slow, add your small cubes of butter a little at a time. Not too slowly, just slowly enough that the addition of the butter doesn’t cause the egg/sugar/butter sludge to fly out of the bowl.

You may not need all the butter. You’ll notice that the meringue will start to deflate almost immediately. That’s okay. The fat content of the butter has that effect. The buttercream is starting to come together when you notice that tiny little bits start to appear around the perimeter of the bowl and the entire mixture is starting to look likes it’s curdling. You’re getting there. Put the mixer on medium high and put in just a few more chunks of butter, then whisk on high until the butter cream looks light and fluffy. If you’re working in a warm environment and you think you’ve already added more than enough butter and you have a liquidy soup that you think will never come together, stick the whole mess in the freezer for a few minutes and then resume whisking.

Once the buttercream is light and fluffy, you can add a bit of ganache for a chocolate buttercream or 1/2 cup of fruit puree for refreshing cake filling.