re: What have I done wrong?

It just looks as though it has curdled slightly from over-beating perhaps … that, or sometimes it can just be that it’s a different batch of icing/confectioners sugar ? I’d be tempted to put the grainy one back in the fridge to chill and then re-beat … Lou x

Lou, S.Yorks UK https://www.facebook.com/SugarandSpiceGourmandise