I made a batch of the Wilton Royal Icing last week and I put it in an air tight container then I put plastic wrap on top of the royal icing and then the lid. It's been sitting on my kitchen counter since.
Is that the proper way to store it or does it need to be refrigerated? Is it still good to use? I'll be using it on Thursday if it's still good.
Need some advice.
You should put it in the fridge. It will keep a long time. Just be sure to stir it really vigorously when you are ready to use it, and you may need to add additional powdered sugar to stiffen it back up.