You mentioned you might have another thread for trouble shooting the SMBC...I think I need you to start that
So, I followed your recipe, only halved it, and directions.
It started out well. Double boiled the egg whites and sugar. Got to 165 by thermometer. whipped it until I got stiff peaks and bowl cooled some. Then started to add the butter. It was room temp. One tablespoon at a time. I never really got the curdled look. and it doesn't seem to have "set". I don't think I got that slapping sound (but not too sure I would know if I did).
I just have these soft peaks\\, it is really smooth. I put it in the fridge for an hour and rebeat...same soft peaks. What gives? I don't think it is right, it would slide right off a cake.