I consider Swiss Buttercream to be one of the best frostings out there, it's light and silky. The added cream cheese and chocolate just made it all that much better.
3 egg whites
3/4 c. white sugar
9 Tbsp unsalted butter, at room temperature
2 (8 oz) pkg. Philadelphia cream cheese, softened
1 1/2 c. semi-sweet chocolate chips
Cook the chocolate chips in the microwave for 2 minutes. Stir. If its not mostly melted cook another minute, repeating until melted. Don't cook until completely melted, you can get the last of the lumps out by stirring it. On that note, stir the chocolate until the lumps are out. Place in the refrigerator to cool, removing every few minutes to stir. Leave in the fridge until the chocolate is no longer hot but not solid either. Around room temperature.
Whisk the egg whites and sugar together in a large bowl.
Place in a pan over water and cook,
whisking, until the egg whites reach 160.
Place the bowl on a towel to dry the water and
prevent water from falling into the mixing bowl.
Pour the egg white into a mixing bowl,
beat on high until doubled in size, opaque white,
and the sides of the bowl are no longer warm.
Drop the butter in, one tablespoon at a time.
Then drop in the cream cheese and beat until it is
of spreadable consistency again.
Beat in the melted and cooled chocolate,
scrape the bowl and beat until smooth.
I used this to filled and frost a three layer 8-inch
cake and even had about 3/4 c. frosting left over.