Simple swiss buttercream cake

Simple swiss buttercream cake

My first attempt at making swiss buttercream. Looked lovely texture when I first made it but by the time I tried to revive it a couple of hours later to fill and cover the cake the texture seemed all wrong. At least I’m guessing that as I have never seen swiss buttercream before. Should I have whisked it or used the panel attachment? I have to confess I tried both ways to try and get the texture back but failed.

Sue's Sugar Art Bakery