How to Get Your Royal Icing to Dry Shiny

The journey to shiny cookies starts with the icing itself. It's important to start your icing off on the right foot before you even apply it to the cookie, so let's start there. 

Adding corn syrup to your icing can result in a softer bite (who among us didn't make a rock hard royal icing when we first got started, amiright?), but it can also affect the visual result, as well. Recipes that include corn syrup typically add between one tablespoon and ¼ cup per 2lb bag of powdered sugar. As with any new “optional” ingredient, I always recommend starting out on the conservative side and adjusting upwards as desired, but I have definitely found that adding corn syrup to my recipe results in a more consistently-shiny icing at the end of the day. 

Overmixing your icing, on the other hand, can cause it to dry more matte. This is one of those aggravating baking terms that can drive you crazy because exactly what the heck does “overmixed” mean?! There is no recipe that says “mix icing for 4 minutes and 17 seconds, and not a second more or your icing will be overmixed.” That would make things too easy. Recipes have to be a little more general, unfortunately (read: “mix for 3-5 minutes”), and so much of the royal icing-making process is in taking visual cues. But an additional two minutes of mixing can be the deciding factor between icing that is perfect and icing that is overmixed, so it's important to keep an eye on your bowl and know when to pull the plug, so to speak. I typically look for my icing to turn a bright white color instead of the dingy wet-powdered-sugar look you start out with. Only once I reach that point do I add white gel food coloring to my bowl; if I add it with the other ingredients at the start, I might miss that visual cue that tells me my icing is done. All that to say, if your icing is drying matte, it might be worth taking a look at how long your mixer is running for.