I've made all types of types of buttercream, Italian, Swiss, French, American, and each has a slightly different ratio of ingredients. But, I was wondering, if there is a "standard" ratio that can be applied to each of these? For example, for my Italian buttercream I use:
-3 egg whites
-2 sticks of butter (227g)
-1 cup of sugar (200g)
Would I achieve equally good results if I applied the above to a french butter cream and substituted egg whites for egg yolks? Is there a minimum ratio for each type to ensure it is stable enough?