If you're a novice cookier, you've likely spent no small amount of time scrolling Reddit's cookie subs, drooling over the gorgeous sugar cookies of confection veterans. And if you're like many people, you're jealous of that glossy royal icing you see in the pictures. The culprit is probably your meringue powder: Even if you use a high-quality meringue powder, it has a satiny finish at best.
So how do you give your cookies that enviable glow without resorting to salmonella-friendly fresh egg whites or watery, whip-resistant boxed egg whites? Two words: corn syrup. Corn syrup helps recipes retain moisture and avoid crystallization, both of which can yield dull results when you're talking about royal icing. Note that we're talking about sweet, wholesome(-ish), naturally derived corn syrup here.
High-fructose corn syrup is a different beast. Makers add enzymes to glucose-based natural corn syrup to change its chemical makeup and introduce fructose. Neither is inherently dangerous in moderation, but they're also not the same thing.
High-fructose corn syrup is much sweeter and not typically commercially available, at least in its pure form. The corn syrup you need for royal icing is available in most grocery stores (and many convenience stores) under brand names like Karo and Crown (or in dozens of store brands). How corn syrup promotes shiny royal icing Corn syrup is an inverted syrup, which is a kind of liquid sugar with different properties than table sugar (thus, it's inverted).
