For anyone who wants to know: Swiss buttercream, in particular this recipe, is far superior to "American" Buttercream. The taste is better and so is the texture and over all quality. Once I found this recipe a few years ago I've never been able to go back to just butter/shortening and powdered sugar. When customers have asked for "sweeter" buttercream I simply add a little more powdered sugar but honestly, once you taste this the way it is you will love it. If u can't see using half a dozen eggs just to "try" a recipe simply half it. What's 3 eggs? :3 Seriously, Try this. There is a reason is has hundreds of thousands of views.
PS: Use real butter. She says you can substitute margarine but from experience it isn't nearly as amazing and it is sort of floppy and melts quickly.