The Unexpected Ingredient That Will Majorly Upgrade Royal Icing

Royal icing is a holiday staple. It's the perfect way to decorate sugar cookies, gingerbread houses, and any other festive sweets. But you can use it year-round for pretty much any occasion.

While royal icing is delicious and versatile, it can be a bit tricky to work with. It's all too easy for the icing to become too runny or too thick; getting that perfect consistency can be a challenge. It also hardens quickly, so you have to be careful not to touch it too much. And if you're not careful, it can crack easily after hardening.

Why is this the case? Royal icing is made with egg whites, which are a finicky ingredient to work with. They can be temperamental, and getting the perfect consistency can be difficult, even for experienced bakers. But Mashed's royal icing recipe is the solution to all of your icing-related woes — and it all comes down to one ingredient.

All you need to take your royal icing recipe to the next level is one unexpected ingredient: glycerine. This clear, odorless liquid is often used in baking as a way to keep cakes moist, but it also works wonders for royal icing. Just a small amount of glycerine will thin out the icing and make it much easier to work with. Best of all, it won't change the flavor of your frosting one bit.

"Royal icing is a meringue-like, white icing that sets with a smooth, firm finish, making it great for using on cookies," recipe developer Catherine Brookes says. "The secret ingredient here is the glycerine. It adds a lovely shine to the icing and makes it a little more soft and workable." You don't need a lot of glycerine; just add a teaspoon to the egg whites while whipping them into stiff peaks.

What you'll get, according to Brookes, is "white icing that sets with a smooth, firm finish, making it great for using on cookies." If you make a large batch, royal icing can be kept in your fridge and used within one week. The next time you're making a sugar cookie recipe or a gingerbread house, try adding glycerine to your royal icing for perfectly decorated sweets.