Swiss Buttercream

(makes enough to frost a 2 layer 9" round cake)

Mix together:
170g egg whites
310g sugar
3g salt

Cook in a double boiler until 185F, then whip until stiff and cooled to 90F.

Whip in 2tbsp at a time:
565g or 5 sticks butter

Notes:
Add cocoa powder, nutella, freeze-dried berries, marshmallow fluff, or other flavorings as desired.