I am trying to find a receipe for buttercream which I can pipe onto cupcakes with a swirl using a 1M nozzle. The receipe I use seems to melt once its been in the room temp for too long and the swirl fades away. The ingredients are usually twice the amount of icing sugar to marg and I find very sickly sweet. Is there anything I can use to give it 'body' and firmness to the buttercream to make the piping design more prominent? I would like a light taste (not very sweet).