Royal icing is a go-to building material for cake decorators, as it’s indispensable for detail-y bits like beadwork on wedding cakes. It pipes extremely well and sets up quickly into very firm and stable structures. That virtue is also royal icing’s curse, at least when it’s applied to something like a cupcake, since it dries into a very brittle coating that shatters when it’s bitten into. Even so, it’s one of those standard tools of the trade that every good baker should know how to make. Start by putting your egg whites and lemon juice into the bowl of a mixer fitted with a whip. If you like you can dribble in a little bit of some sort of extract as well…vanilla, lemon or almond.
Whip for about 30 seconds until the mixture is frothy…
…then with the machine running, start adding the powdered sugar.
Whip about five minutes until it’s thick and glossy, like so:
Since exposure to air will start drying the icing out almost immediately, you’ll want to transfer this to a pastry bag or other airtight container immediately.
Two egg whites plus three cups of powdered sugar plus a squeeze of lemon juice. That’s the standard formula that I learned years ago, though these days, because of concern over the use of raw eggs, more and more people are using meringue powder to make royal icing. I’d need to consult with an expert on salmonella, but I personally have a hard time seeing how any bacteria would be able to survive in so much sugar, which is as lethal to microbes as salt. Perhaps the concern is that if by some extraordinary means a few bugs survived in the icing, they might thrive on/in a cake. I find that a stretch as well, but do as your conscience dictates. I’ll include both recipes. Here’s the conventional:
2 egg whites (pasteurized is ideal for people living in the US)
12 ounces (3 cups) powdered sugar
1/2 teaspoon of lemon juice (or a few drops of lemon or vanilla extract)
Put the whites in the bowl of a mixer fitted with a whip. Whip on high until they’re foamy, then with the machine running add the powdered sugar and juice/extract. Whip about five minutes until the icing is thick and glossy. OR
3 tablespoons meringue powder
16 ounces (4 cups) powdered sugar
4 ounces (1/2 cup) water
1/2 teaspoon lemon juice or a few drops of lemon or vanilla extract
Combine the meringue powder and powdered sugar in the bowl of a mixer fitted with a whip. Mix the two on low speed, then turn the mixer up to high and add the water and juice/extract. Whip about five minutes until thick and glossy. Adjust the consistency with more water if necessary.
However you do it, transfer the icing immediately to a pastry bag or an airtight container until you’re ready to use it, because this icing will harden quickly with exposure to air.