Royal icing is a super-sweet white icing that hardens when exposed to air. It’s ideal for fine details on cookies or cakes. You can also use it to make your own sprinkles (see DIY Sprinkles).
Makes about 475 g / 3 cups
Difficulty: Easy
Make Ahead and Storage: The royal icing can be made ahead and stored at room temperature, covered directly with plastic wrap, in an airtight container for up to 5 days.
1. In the bowl of a stand mixer fitted with the whisk attachment (or in a large bowl, using a hand mixer), whip the egg whites on medium speed until lightly frothy, about 1 minute. Gradually add the powdered sugar, mixing on low speed, and then mix until the icing is glossy and smooth, 1 to 2 minutes. Add the vanilla and mix to combine. If the icing is too thick to pipe, thin it out with water; if it is too thin, add more powdered sugar, mixing until smooth (see photo).
2. Keep the icing covered with plastic wrap placed directly against the surface until ready to use—it hardens in seconds when exposed to air.
★ pro tip
You can also make the icing with meringue powder (available at cake supply stores or online). Substitute 30 g / 3 tablespoons meringue powder and 91 g / 6 tablespoons water for the egg whites.