Hi, 

So I strongly dislike the taste of American buttercream because it is too sweet and greasy. Most people that I know also dont like it . I know that a lot of people use a meringue frosting which is lighter and fluffier but also takes FOREVER to make and is very risky. I dont want to use egg whites due to allergy reasons that many people have. But I want something that is stiff and smooth and works well under fondant. 

I tried a swiss meringue with meringue powder and unfortunately it was a FAIL. I found this recipe.

Sawsen's Egg Free Swiss buttercream recipe (SEBC)

 and was wondering if anyone ever tried it. The recipe uses protein powder. The recipe looks very promising. It is super smooth and stiff and it claims that it tastes like VANILLA ICECREAM (never tasted buttercream that tastes like that). Let me know if you have a recipe or have tried this recipe. Thanks

so..... what's the 'protein powder' consist of?

wheat gluten, egg white, or what?

The recipe says that you can use soy protein powder or whey protein powder. It is basically a substitution for eggs in frosting. 

I've done egg free meringue buttercream before and it turned out quite well. I did it for a group of girls a year ago, as they were wanting to learn cake decorating and one is allergic to eggs. I still get comments about how good the buttercream was. I used a recipe for aqua faba. The meringue is made with liquid from a can of garbanzo beans, and there are several recipes out there.  I don't remember which recipe I used exactly.