Quick answer
Royal icing wins for cookies, gingerbread and any piped decoration that needs to dry rock hard, such as lace or string work. Buttercream wins for anything meant to be eaten as a soft cake frosting, since royal icing dries brittle and very sweet. Most decorators use both: buttercream on the cake itself, royal icing for the small hard accents.
Wilton Meringue Powder, 16 oz
Meringue powder is pasteurised dried egg white, which is the standard way to make royal icing without raw egg, and 16 ounces is enough for a season of cookie work.
Best for: royal icing without raw egg
Check price on AmazonRoyal icing wins at exactly one thing buttercream cannot do: drying into a hard, glass-like set that holds fine detail indefinitely, which is why it is the standard choice for decorated cookies, gingerbread houses and piped string work or flowers meant to be handled without softening. Buttercream wins at everything else, because it stays soft, tastes like frosting rather than like set sugar, and is what almost every cake is actually covered in.
The two rarely compete directly, since they are built for different jobs: royal icing is egg white (or a substitute) and powdered sugar beaten until it dries hard, while buttercream is a whipped fat meant to stay soft indefinitely at room temperature. Where they do overlap is food safety. Traditional royal icing recipes use raw egg white, and meringue powder, pasteurized dried egg white, is the standard way modern kitchens avoid that. Neither Wilton meringue powder product on this site is being described as making a recipe tested or safety-certified; it is simply the pasteurized alternative to raw egg white that most royal icing recipes call for today.
Royal icing or buttercream: what changes with the icing?
The specifications below explain why the two rarely substitute for each other directly.
| Specification | Royal icing | Buttercream |
|---|---|---|
| Sets by | Drying hard, like set sugar glass | Cooling and crusting; stays soft |
| Texture once finished | Brittle, snaps rather than bends | Soft, spreadable, holds a piped shape |
| Sweetness | Very sweet; mostly powdered sugar | Sweet, but softened by fat and air |
| Traditional egg component | Raw egg white, historically | None in American buttercream |
| Common pasteurized substitute | Meringue powder | Not applicable |
| Typical use | Cookies, gingerbread, fine piped detail | Covering and filling a cake |
| Covering a whole cake | Rare; too hard and sweet in quantity | Standard practice |
Why does royal icing need meringue powder instead of raw egg white?
Traditional royal icing recipes are built on raw egg white, which is what dries into that hard, glossy finish. Meringue powder, pasteurized dried egg white reconstituted with water, is the standard modern swap, and it exists specifically to remove the raw-egg question from a recipe that otherwise has no cooking step to do it for you.
This is genuinely worth doing rather than skipping when the icing is going on cookies for children, older guests, anyone pregnant, or a large mixed crowd where you cannot ask everyone about their own risk tolerance. A 16 ounce can covers a season of cookie decorating, while the 4 ounce size suits occasional royal icing work, since it is used a few tablespoons at a time and a large tub can sit open for a long while between uses.
What consistency of royal icing do you actually need?
Royal icing is not one fixed recipe; the same base is thinned with water to different consistencies for different jobs, and getting the wrong one is the most common reason a first attempt looks messy.
| Consistency | Behavior | Used for |
|---|---|---|
| Stiff peak | Holds a sharp peak without slumping | String work, flowers, upright details |
| Piping, medium | Holds a line but the peak softens | Outlining cookies, lettering |
| Flood, thin | Self-levels smooth within seconds, then dries glassy | Filling in an outlined cookie |
Can royal icing cover a whole cake instead of buttercream?
Technically yes, but it is rarely done, and for good reason. A cake fully coated in royal icing dries into a hard, brittle shell that is difficult to cut cleanly and much sweeter per bite than buttercream, since royal icing is almost entirely powdered sugar with very little fat to soften it. It also has none of buttercream's forgiving, re-spreadable texture while working, so smoothing a large surface is far less controllable. Royal icing's genuine strength stays in the areas buttercream cannot reach: hard piped flowers, lace panels, and string work that has to survive handling without softening, all of it usually made ahead and set onto a buttercream-covered cake rather than replacing the buttercream itself.
Before this cake leaves the kitchen
If a royal icing recipe still calls for raw egg white rather than meringue powder or a pasteurized egg product, that is worth swapping when baking for children, older guests, anyone pregnant, or any crowd whose risk tolerance you cannot individually ask about. Plain American buttercream carries no egg white and no raw-egg question at all, though it does soften in a warm room, which is a structural issue rather than a safety one. Ask about allergies before baking for someone else, since both icings involve eggs or dairy depending on the recipe, and selling either one is governed by your state's cottage food law, which varies.
What this job actually needs
Wilton Meringue Powder, 16 oz
$33.90Meringue powder is pasteurised dried egg white, which is the standard way to make royal icing without raw egg, and 16 ounces is enough for a season of cookie work.
Best for: royal icing without raw egg
Check price on AmazonAmazon prices move often, so check before you buy.
Ateco 810 Plain Tube Set, Sizes 0 to 9, 10 Piece
$16.49Ten plain rounds in graded sizes, which is the set that actually gets used: dots, pearl borders, filling macarons and writing all come off a plain tube.
Best for: dots, borders and writing
Check price on AmazonAmazon prices move often, so check before you buy.
KitchenAid KFE5TS Flex Edge Beater for 4.5 and 5 Quart Tilt-Head Mixers
$49.99A flexible silicone edge that wipes the bowl wall as it turns, which is the single attachment that most improves buttercream, because unmixed butter clinging to the side is what makes a batch look curdled.
Best for: buttercream and creaming butter and sugar
Check price on AmazonAmazon prices move often, so check before you buy.
Questions people ask
- Does royal icing use raw eggs?
- Traditional royal icing recipes are built on raw egg white, which is what gives the icing its hard, glossy dried finish. Most modern recipes instead use meringue powder, which is pasteurized dried egg white reconstituted with water, specifically to remove the raw-egg question. A recipe that still lists raw egg white can usually be swapped for meringue powder or a pasteurized egg white product with no other change to the method.
- Can I substitute meringue powder for egg whites in royal icing?
- Yes, this is the standard modern approach rather than a workaround. Meringue powder is pasteurized dried egg white made specifically for this use, reconstituted with water according to the package directions before it goes into the icing. It is worth doing whenever the icing is for children, older guests, anyone pregnant, or a crowd where you cannot ask everyone about their own risk tolerance around raw egg.
- Is royal icing sweeter than buttercream?
- Yes, noticeably. Royal icing is almost entirely powdered sugar and dried egg white or meringue powder, with essentially no fat to soften the sweetness. Buttercream, whether American, Swiss or Italian, contains a substantial amount of butter, which tempers the sugar and gives a rounder flavor. This is the main reason royal icing is used for small accents rather than as a full cake covering.
- Can you put royal icing on a cake instead of buttercream?
- It is possible but rarely done, because royal icing dries into a hard, brittle shell rather than staying soft, and it is much sweeter per bite than buttercream since it has almost no fat in it. Most decorators use royal icing only for small piped accents, such as flowers, lace or string work, made separately and set onto a cake that is still covered in buttercream, rather than replacing the buttercream entirely.
- How long does royal icing take to dry hard?
- Drying time varies with the icing's thickness, the humidity in the room, and how much water was used to thin it, so there is no single reliable number to give. A thin flooded layer on a cookie generally sets to the touch sooner than a thick piped string-work detail. High humidity slows drying noticeably, which is why royal icing decorators commonly work with a dehumidifier or fan running in a damp climate.
Related pages
How this page was put together
Researched from pan geometry, published manufacturer capacities, published serving conventions and university extension guidance. Not hands-on testing, and not professional advice.
Figures are labelled as derived, published or trade convention. Where no honest figure exists, the page says so rather than filling the gap.