Renshaw Ready-to-Use Royal Icing 1 "Very disappointed" Mrs HarrallAger 28 December 2016 I bought this ready made royal icing to save time. I used it to cover my Christmas cake and did rough peaks and then added home made penguin decorations. I left it in a dry cool room to set. The next day I was horrified to see that the icing has not set at all and all the peaks have disappeared. My cake is ruined. I would not recommend this product for rough icing as it doesn't hold its shape or dry adequately. A note from the team Thank you for placing your review. We're sorry to hear of your experience and we'll be in touch shortly. For a firmer, stiffer finish the instructions suggest adding a little icing sugar.