Most frosting hardens over cake. In fact, a professional looking cake depends upon it. At times, though, your frosting might become too firm in the refrigerator, so gentle microwaving or additional liquid might be required to soften the frosting and whip it back into shape.

Mix your batter with a light hand. “Baking fluffy, moist cupcakes is all about creating air bubbles in your batter that expand in the oven,” she says.

If your buttercream is too cold, the butter and meringue will split apart. Typically this will make it look sort of curdled. You might see small clumps of butter with white liquid oozing around it. To fix split buttercream, all you have to do is gently heat the buttercream.

Once your royal icing has been piped on, you can set it out to dry. After just 15 to 30 minutes, it will form a thin crust on the surface, but it generally will stay wet underneath for several hours. I usually set my cookies out (in a single, flat layer, on parchment-lined baking sheets) overnight to dry.

Canned Frosting Hacks: Royal Icing Royal icing is a popular decoration for cookies. It hardens when it dries, giving the cookies a smooth appearance and creating a base for adding details.

How Do You Make Cookie Icing That Hardens? The trick to getting sugar cookie icing to harden is in the ingredients, powdered sugar, milk, and corn syrup. The extract adds a boost of flavor. The small amount of corn syrup achieves that shiny, glossy surface.

Since icing does not dry hard, stacking iced cookies is not recommended. Individual cookies can be packaged in a treat bag once the icing has set. For best results, store cookies at room temperature in a single layer in a cookie or cake box.

“Try to make all the cookies uniform—they bake more evenly and they look much better,” says Lipton. “The easiest way to do this is to use a cookie scoop, essentially a small ice cream scoop.” She recommends using OXO’s Medium Cookie Scoop for the best results.