Why It Works
- Cooking over a water bath eliminates concerns over raw egg whites, while also helping the powdered sugar to dissolve.
- Fat carries flavor, so using a splash of cream makes vanilla taste more intense.
- Using salt and acid (cream of tartar) balances the sugary sweetness.
- Silver rum adds a subtle flavor, without darkening the icing like vanilla.
- Creaming helps minimize the grit of powdered sugar.
Let's be honest—royal icing is not known for being delicious. At best, it's a sweet and simple paint for rolled sugar cookies, but at worst, it's little better than Elmer's glue. Even so, bakers come back to this classic icing time and again, because it's as easy to make as it is to use, and it guarantees a gorgeous, smudge-proof facade for decorated cookies.
Typical recipes involve two parts egg white to nine parts sugar by weight, a ratio that ensures this ultra-low-moisture icing can dry to a crisp. Given that it's mostly sugar by weight, it's important to acknowledge that royal icing is, by nature, pretty dang sweet. There's no point in denying it, but that doesn't mean royal icing lacks the capacity to evolve.
For Greater Depth of Flavor, Use Organic Powdered Sugar
First and foremost, making the switch from conventional to organic powdered sugar will instantly give royal icing a greater depth of flavor. That's because organic powdered sugar still contains a portion of its natural molasses content, so, instead of tasting like pure sucrose, it has the mellow sweetness of raw cane sugar.
Most organic powdered sugars are also made with tapioca flour rather than cornstarch, which reduces the sense of grittiness in royal icing.
The downside to organic powdered sugar is that the presence of molasses gives the icing a decidedly ivory hue, so it may not be the best choice for super-snowy designs or light pastels. But when the icing is tinged with bright and vibrant primary colors, that off-white shade is easy to overcome. (More color comparisons and information on conventional versus organic, tapioca-based powdered sugar can be found in my article on the subject.)
How to Balance Flavors in Royal Icing
Another simple way to improve classic royal icing is to make sure it's well seasoned. When making a sauce, chefs always work to ensure it has the right salt, acidity, and aromatics to bring out its best flavor, and I feel it's important to treat royal icing the same way—at least, if you plan on eating it.
Obviously, that means starting with plenty of salt to tame the icing's sweetness, but also adding a bright burst of acidity. For me, that means cream of tartar, which has a neutral flavor that won't interfere with whatever cookie I have planned. A splash of vanilla extract is a no-brainer for almost any type of frosting, but less intuitive is a spoonful of silver rum. Made from cane sugar, rum has a natural affinity for dessert, adding a sense of richness and complexity without darkening the icing, as most other spirits would.
The Benefits of Cooking Over a Water Bath
Royal icing is typically a raw preparation, with everything just mixed up in a bowl, but I've found it has a much creamier consistency if cooked over a water bath. Not only does this technique ensure the powdered sugar is fully dissolved, and therefore less gritty, it effectively pasteurizes the egg whites, too.
I, being both callous and cavalier, have no qualms about raw-egg icings (their extremely low-moisture/high-sugar formulation makes it nigh-impossible for bacteria to thrive), but for many, this extra step can lay the fear of raw eggs to rest. Plus, you get a creamier royal icing with the ingredients you have at home already—no special-ordering meringue powder or pasteurized eggs.
If you're actually concerned about raw eggs, cook the royal icing to 150°F (66°C) over a water bath, and hold it there for three minutes. If you're more inclined to live on the edge, simply cooking until it's hot to the touch is more than enough to ensure the powdered sugar has thoroughly dissolved.
Once the icing's hot, I add a bit more powdered sugar to thicken things up. It dissolves with the residual heat of the icing, and saving it for last keeps the icing thin and easier to stir while it's over the water bath. From there, I beat the royal icing until it's thick, light, and perfectly creamy.
The goal of this process is to ensure the royal icing is silky-smooth, not to whip it up like cream; excessive aeration would only introduce pesky air bubbles that would later pock your ideally smooth icing. For that reason, creaming with the paddle attachment is vastly preferable to whipping with a whisk (although, if need be, you can certainly make do with a hand mixer set to low speed).
How to Thin Royal Icing With Cream
At this stage, the royal icing is thick enough to handle chunky designs (like the buttons on a gingerbread man, or little rosettes on a cake), and it's also the least messy option if you plan to decorate some cookies with the kid. But if you'd like to glaze the tops of cookies with an even sheen of royal icing, or attempt a more ambitious, elegant design, it needs to be thinned first.
Thinning the icing makes it much more difficult to work with, a recipe for disaster for small children still honing their fine motor skills. So, please bear in mind: Thinned royal icing should be limited to use by teenagers and adults.
Most recipes rely on water to thin royal icing, but I've found cream to be far superior. To continue my analogy regarding a properly made sauce, a small amount of cream adds richness, improving the flavor and mouthfeel of the icing all around. Since fat carries flavor, it also enhances our perception of vanilla, so the icing seems more aromatic as well. These subtle improvements work together for an icing that seems less sweet, as verified through several blind tastings among my friends.
We're not talking a lot of cream; just three tablespoons in a two-and-a-half-cup batch. If that's a problem, try using plain, unsweetened, full-fat coconut milk instead. Of course, water will do in a pinch, but it's not a 1:1 swap, so take care when experimenting on your own, adding less at first and then thinning as needed from there.
The only downside to the addition of cream is that the icing may curdle if mixed too long. Fortunately, that's only a risk if you leave the icing on the stand mixer unattended (a technique some bakers use to keep royal icing from crusting over in the bowl).
Properly thinning the icing with cream is largely a matter of precision measurements, but unless you start by beating an egg white to weigh out a hyper-specific amount, there will always be an element of personal judgment in determining whether the icing is too thick or too thin. The process becomes intuitive when you've done it countless times before, but here's the test I use at home.
Lift up the beater and drizzle the icing back into the bowl, making a figure 8 pattern. If the figure 8 is still sitting there after eight seconds, the royal icing is too thick, and your designs may be lumpy. If the figure 8 melts away much more quickly, the royal icing is too thin, and your designs will run and drip.
To adjust, simply stir in a few drops more cream to thin, or another teaspoon of powdered sugar to thicken, repeating (or alternating between the two) until the figure 8 disappears into the surrounding icing after exactly eight seconds. It can be a bit of a cereal-and-milk situation, going back and forth a few times, but with patience, you'll get it just right.
When royal icing can hold its shape for eight seconds, it's said to have a "flood consistency," a particular stage that allows royal icing to both outline and fill a shape. It's this unique viscosity that lets professionals glaze an intricately shaped cookie without any drips.
Adding Color to Your Royal Icing
Once it's adjusted to flood consistency, my royal icing can be divided into as many as four bowls to color with gel paste—liquid dyes will throw off the consistency too much. (To get really fancy, you can even add a pinch of pearl dust to give it a subtle shimmer.)
If you'd like more colors, I'd recommend making a double or triple batch, or else the quantity of each color will be less than half a cup, which isn't much if you've got a lot of cookies to frost. As with any recipe, use caution when multiplying each ingredient for a larger batch, as even one small error will derail the icing.
If you've divvied up the icing to color, cover each bowl in plastic wrap to prevent it from crusting over when not in use; royal icing can begin to dry within 60 seconds, especially around the edges of the bowl, where splashes let it spread out thin. After coloring the icing, transfer it to a parchment cone or a disposable pastry bag coupled with a super-fine tip (I use Wilton #3).
It may be tempting to just drop the tip in the bag and be done with it, but with royal icing, I recommend using couplers, which make it easy to remove and clean the piping tips should they become clogged by a wayward flake of crusty icing.
Bagging the icing minimizes its exposure to air, so you don't have to worry about it crusting over, and reduces the risk of a messy spill or just accidentally jabbing your finger in the bowl. (Like paint, dyed royal icing has a way of getting everywhere if you're not paying attention.) If you wanna get fancy with cookie decorations, check out my royal icing tutorial for more photos, videos, and ideas.
So preheat that oven, start rolling out those sugar cookie cutouts, put on your favorite elf hat, and let the holiday baking begin!
The Royal Icing Figure 8 Test
18 ounces organic powdered sugar (4 1/2 cups; 510g), divided, plus more if needed (see notes)
2 1/2 ounces egg whites (1/4 cup; 70g), from 2 large eggs
2 teaspoons (10ml) silver rum or water
1 1/2 teaspoons (7ml) vanilla extract (see notes)
1/2 teaspoon (2g) Diamond Crystal kosher salt; for table salt, use half as much by volume or use the same weight
1/4 teaspoon cream of tartar
1 1/2 ounces heavy cream (3 tablespoons; 40g), plus more if needed (optional; for thinning royal icing, if desired)
Gel paste food coloring, optional
To Make the Icing: Measure 16 ounces powdered sugar (4 cups; 450g) and place in the bowl of a stand mixer, then add egg whites, rum, vanilla, salt, and cream of tartar. Stir with a flexible spatula to form a smooth paste, then set over a gently simmering water bath in a 3-quart saucier and stir until paste is hot to the touch, or about 150°F (66°C) on an instant-read thermometer. Transfer to stand mixer fitted with a paddle attachment, add remaining 2 ounces powdered sugar (1/2 cup; 60g), and mix at low speed to combine. Increase speed to medium and beat until thick and frosting-like, about 20 seconds or until the mixing bowl feels cool to the touch. Use immediately as a thick frosting or to make chunky decorations, like the buttons on a gingerbread man or little rosettes on a cake; color, if desired, according to instructions in step 3. For a thinner royal icing, used to make an even glaze for the tops of cookies, or to attempt a more ambitious, elegant design, thin according to instructions in step 2.
To Thin the Icing: Reduce speed to low, add cream, and continue mixing until smooth. Remove bowl from mixer and lift paddle attachment, moving it in a figure 8 pattern as icing streams back into bowl. If the figure 8 disappears in exactly 8 seconds, the icing is ready to use as a cookie glaze. If it melts away faster, thicken by adding a spoonful of powdered sugar. If it takes longer than 8 seconds to disappear, thin by adding a few drops of cream. Repeat this test, making adjustments as you go, until the figure 8 takes exactly 8 seconds to disappear.
To Color the Icing, if Desired: Divide icing among several small bowls, one for each color you'd like to prepare. Cover each with plastic wrap pressed directly against the surface. Working with one bowl at a time, stir in a few drops of gel paste. When your desired color has been achieved, immediately transfer to a disposable pastry bag fitted with a #3 pastry tip, or a parchment cone. (For ease of use, I like to stand the bag/cone upright in a small drinking glass.)
To Glaze the Tops of Sugar Cookies: Leaving a 1/8- to 1/4-inch margin (or more, depending on size of cookies), outline baked and fully cooled rolled sugar cookie cutouts with royal icing, then roughly drizzle the interiors with more icing, using the piping tip to nudge it into an even layer. Work quickly if topping with sprinkles or a secondary icing color, as royal icing will form a crust within 90 seconds. If you'd like to read more on the basics of decorating, check out my royal icing tutorial for lots of photos, videos, and ideas. For cookies to keep around the house, allow royal icing to air-dry until firm, about 4 hours. For cookies to package and ship, allow royal icing to dry until hardened through and through, about 6 to 8 hours more.
Cookies frosted with royal icing can be stored up to 1 week at room temperature; in a pinch, their shelf life can be extended to about 10 days with refrigeration. Unfortunately, cookies with royal icing should not be frozen, as the water in the royal icing will form ice crystals that will melt as liquid water when thawed, creating a blotchy appearance on the surface of the frosting.
Organic powdered sugar has better flavor and a less gritty texture than conventional, but it's slightly off-white as a consequence. If your decorative needs demand a truly white icing, stick with conventional powdered sugar and grab a bottle of clear vanilla. Don't be misled by fancy packaging: All clear vanilla extracts are imitation, the price of perfect clarity.
|Nutrition Facts (per serving)|
|Amount per serving|
|% Daily Value*|
|Total Fat 1g||1%|
|Saturated Fat 0g||2%|
|Total Carbohydrate 26g||9%|
|Dietary Fiber 0g||0%|
|Total Sugars 25g|
|Vitamin C 0mg||0%|
|*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.|