Why It Works
- A higher proportion of sugar to egg white keeps this meringue glossy and dense, for easy piping and cookies that stay true to form as they bake.
- Toasted sugar tames the overall sweetness of the meringue while adding notes of caramel.
- The acidity in cream of tartar adds a counterpoint to the meringue's sweetness.
- A long, slow bake-time ensures the meringues dry completely, for crisp and light cookies that dissolve on the tongue.
I love meringue mushrooms. I've been making them to garnish my annual bûche de Noël, or Yule log, since I was a little kid, and my love for them has only deepened over time. Slowly, they've transformed from the clumsily assembled, hyper-sweet, Styrofoam-like sugar puffs of my childhood to something a bit more flavorful and sophisticated but every bit as fun.
Traditional meringue mushrooms start with a hard meringue, one that's made with more sugar than egg whites, and for that, I like to fall back on my basic Swiss meringue. Because it's fully cooked on the stovetop, it pipes true to form when baked at low heat, so I don't have to wonder how my meringue caps and stems may inflate or deform as they bake. What I pipe is what I'll get, so from the very start, I know how my mushrooms will look in the end.
While meringue mushrooms are most often used as a garnish, with the actual dessert experience coming from the Yule log itself, I like mine to have enough flavor to stand on their own. To that end, I use toasted sugar to lend some caramel notes to the meringue and bring its sweetness down a notch. A pinch of salt and cream of tartar help round out its flavor as well, along with a generous splash of vanilla extract (which can be adjusted to taste).
For even more flavor, I buff the finished meringues with a high-fat cocoa powder (while I prefer the darker flavor and color of Dutch, natural cocoa powder works just as well). Finally, I glue the caps and stems together with some top-notch chocolate.
The brand and style of the chocolate hardly matter so long as you love its flavor, but dark chocolates in the 70% range tend to be easiest for beginners to temper (see our guide to the best supermarket dark chocolate bars for some suggestions on brands). That said, milk chocolates rich in cocoa butter are a solid option as well, so long as they don't contain any added palm oil (all of our favorite supermarket milk chocolate bars do nicely in this context).
With so many good ingredients involved in their making, these meringue mushrooms can't help but be a treat of their own, making them so much more than a cute garnish. Just don't expect to be wowed by the flavor of those made with white sugar; rubbed in starchy, low-fat cocoa; and pasted together with cheap chips. Recipes as simple as this can't be better than the sum of their parts.
I've covered how to make Swiss meringue pretty extensively in the past, so I'm going to jump straight into the mushroom-making technique.
I start by dividing the meringue between two disposable pastry bags, one fitted with a 1/2-inch round tip and the other with a 1/4-inch round tip. This makes it easy to pipe mushroom caps and stems both large and small, wide and skinny, thick and thin, for a more diverse arrangement in the end.*
*It will be hard to resist cracking a few sophomoric jokes as you pipe the stems, but their questionable appearance will resolve when the mushrooms are assembled later on.
To pipe the caps, I hold the bag perpendicular to a parchment-lined half-sheet pan, with the tip about 1/4- to 1/2-inch above the surface. By squeezing on the bag without raising the tip, I can pipe a wide, flat disc like the cap of a shiitake. By slowly raising the tip about 1/2-inch as I pipe, I can create a more rounded, button mushroom–like shape. By continually raising the bag as I pipe, I can create the stems.
The biggest trick is to stop squeezing the bag before moving the tip away when you're done, so the meringue doesn't continue to flow out in a trail; otherwise, the process is fairly intuitive and easy to figure out on the fly. Plus, the recipe intentionally creates a little excess meringue so you can comfortably experiment with different piping styles. This leaves plenty of room to practice and learn. And crack jokes. And make questionable Instagram videos (as the entire Serious Eats team gathered to do when I was piping this batch).
After the caps and stems have been piped, any exaggerated peaks or deformities can be smoothed away with a wet fingertip (just dip your index finger in a dish of water between each one). Smoothing and molding the caps with water can create wrinkles and folds in the meringue as well as water spots, and while these might be "defects" on a fancy meringue cookie or macaron, they only make these "mushrooms" look more natural and organic.
See what I mean? But I'm getting ahead of myself. Before the meringues can look like mushrooms, they have to be baked.
When they go into the oven, the meringues will look glossy and wet, with a bright white-to-ivory hue (depending on how darkly the sugar was toasted). But after a long stint in a low oven (about three hours at 225°F (110°C), although the timing can vary depending on the size, shape, and quantity), they'll turn a matte beige and feel firm and dry to the touch. Once baked, I cool the meringues to room temperature in the oven itself, with the door tightly closed, letting them further dry as they cool.
The timing of the cooling phase can vary a lot from oven to oven (some retain heat better than others, some have a venting system, some have a poor seal on the door), but it takes about four hours for me; long enough that I generally like to save this project for later in the afternoon, so I can let the meringues cool overnight. Otherwise, the baking and cooling phase can end up occupying my oven for the better part of the day, which isn't ideal during the holidays.
Once the meringues cool and dry, I dust them with a high-fat cocoa. I've found the mushrooms tend to look more realistic when the caps are darker than the stems, so I go heavier on the former than the latter, but that's mostly a matter of personal taste.
Next, I rub that cocoa into the surface of the meringue, buffing the caps and stems until they're a mottled brown all over. If needed, I may dust with more cocoa to get a deeper color here and there. It's a little messy, but truly hard to go wrong; the more smudged and "dirty" the mushrooms look, the better.
At this point, the meringues can be used right away for assembly or stored for up to a week before final assembly (wrap them tightly in plastic or transfer them to an airtight container). The cocoa dusting keeps the pieces from sticking together, so they can be jumbled together in a bag without any fuss.
Before assembling the mushrooms, however, I like to sort through the pieces, mixing and matching caps and stems to find the size and shape combinations that look best to my eye.
I find something about the process incredibly soothing, like working on a puzzle, but don't fuss over it too much if you're not as enthralled. The mushrooms tend to look cute no matter how they're put together.
To assemble the mushrooms, you'll need to temper a little chocolate; it might seem like a pain, but if the chocolate is simply melted, rather than tempered, it won't set up nicely at room temperature, so the mushrooms will have to be stored in the fridge and served cold (gross). The melted chocolate may also develop a mealy consistency over time (also gross).
The chocolate can be tempered according to any of the methods in our guide to tempering or the method described in my cookbook. Once tempered, spread a little chocolate over the bottom of a mushroom cap, then dip the very tip of a mushroom stem into the chocolate as well, and join the pieces together, with a gentle twist to secure the cap and stem together—it's more about balancing the pieces together in the thick chocolate than achieving a snug fit. Arrange the assembled mushroom upside down on the empty baking sheet, pressing the stem firmly into the cap if it seems unstable.
If a stem seems especially precarious, it can be propped up against the rim of the baking sheet, or a neighboring mushroom. Don't worry about stems that lean or shift a little, they'll look great when flipped back over, but do fix any stems that fall over altogether.
Once the mushrooms are upright again, you may want to dust them in a bit more cocoa powder, so they look as if they've freshly emerged from a patch of soft earth. The finished mushrooms can be stored in an airtight container for another week or used right away, but do keep them stored until the last minute. They're likely to soften when left out in a humid kitchen environment.
Whatever recipe you use for the Yule log itself, these meringue mushrooms will make a worthy garnish, lending both charm and flavor to this iconic Christmas dessert.
6 ounces egg whites (2/3 cup; 170g), from 5 to 6 large eggs
9 ounces toasted sugar (1 1/4 cups plus 1 tablespoon; 255g) (see notes)
1/4 teaspoon (1g) Diamond Crystal kosher salt; for table salt, use about half as much by volume or the same weight
1/4 teaspoon cream of tartar
1/2 ounce (1 tablespoon; about 15g) vanilla extract, or more to taste
4 ounces finely chopped dark or milk chocolate (about 2/3 cup; 115g)
Getting Ready: Adjust oven racks to upper-middle and lower-middle positions, and preheat the oven to 225°F (110°C). Line 2 half-sheet pans with parchment, and fit 2 large pastry bags with plain, round tips (we recommend using one 1/2-inch round tip and one 1/4-inch round tip to create mushroom caps and stems, both large and small). Twist the tip so the narrow end of the bag twists closed, then tuck a bit of the bag into the tip to "seal" so the meringue won't flow out prematurely. Slide each prepared pastry bag into a large pilsner glass (or a similarly tall, narrow container), and roll the opening of the bag over the rim of the glass, so it stands open and easy to fill.
For a Stand Mixer With a Bowl-Lift Design: Tear off a long strip of foil and crumple it into a thick ring. Place it in the bottom of a 3-quart saucier, or similarly large, wide pot, and fill with roughly 1 1/2 inches water. Place over high heat until bubbling-hot, then adjust the temperature to maintain a gentle simmer. In a stainless steel stand mixer bowl, combine egg whites, toasted sugar, salt, and cream of tartar. Set over the steaming water so that the bowl is resting on the foil ring and touching neither the water nor the pot itself. Cook, stirring and scraping constantly with a flexible spatula, until egg whites register 175°F (79°C) on a digital thermometer; this should take no longer than 8 to 10 minutes. Transfer bowl to a stand mixer fitted with a whisk attachment.
For a Stand Mixer With a Tilt-Head Design: Fill a large pot with a few inches of water. Place over high heat until bubbling-hot. In a large heatproof glass or ceramic bowl, combine egg whites, toasted sugar, salt, and cream of tartar. Set bowl over the steaming water, then cook, stirring and scraping constantly with a flexible spatula, until egg whites register 175°F (79°C) on a digital thermometer; this should take no longer than 10 minutes. Scrape mixture into the stand mixer bowl and fit stand mixer with a whisk attachment.
Preparing the Meringue: Whip the meringue on high speed until glossy, stiff, and thick, about 5 minutes (the timing can vary substantially depending on the equipment involved, so use the textural cues as your primary guide). When well-whipped, reduce speed to medium-low and add vanilla extract. Adjust salt and vanilla to taste, bearing in mind the meringue will taste less sweet once it has baked. Transfer the meringue to the prepared piping bags and have a small dish of water nearby.
For the Mushroom Caps: Hold the piping bag perpendicular to the parchment-lined sheet pan, with the piping tip about 1/4- to 1/2-inch above its surface. For flat, shiitake-like mushrooms, don't lift or move the bag whatsoever, simply squeeze firmly so the meringue is piped out in a disc-like shape; be sure to stop squeezing before moving the tip away when finished (a quick, lateral move left or right will make a clean break). For rounder, button mushroom–like shapes, slowly lift the piping bag while squeezing, then stop squeezing before moving the tip away. Repeat until the tray is filled with "caps" in assorted sizes and shapes, leaving at least 1/2-inch between each cap.
Dip your index finger in the dish of water, then smooth and flatten the pointed peak of each cap, re-wetting your fingertip between each one. This process may create wrinkles and folds in the meringue, and residual moisture can result in water spots, contributing to a more organic appearance in the finished mushroom.
For Mushroom Stems: Hold the piping bag perpendicular to the parchment-lined sheet pan, with the piping tip about 1/4-inch above its surface. Begin squeezing out the meringue, while slowly lifting the bag straight up; when the stem has reached the desired length, stop squeezing and lift the bag straight up until the meringue breaks away. Stems in assorted widths and heights can be created by varying the speed of piping and lifting. If you like, the stems can be piped at slight angles, or with a slightly spiraled effect, to create a wider array of shapes. Repeat until the tray is filled with "stems," leaving at least 1/2-inch between each one. As with the caps, the mushroom stems can be molded, adjusted, or smoothed with a wet fingertip. Don't worry if any stems fall over or lean to one side or show water spots, as all of these "defects" will give the finished mushrooms a more organic appearance.
Baking the Meringues: Place both trays of meringue in the oven. Bake until the caps and stems feel dry to the touch and peel easily from the parchment when lifted away, although a firm squeeze may reveal their interior texture to still be quite soft. This slow-bake should take about 3 hours but can vary depending on the accuracy of the oven as well as the exact number and size of the mushroom pieces. In ovens with uneven heat, rotate the sheet pans and switch their positions about halfway through. At the end of baking, the meringues will have taken on a light ivory to beige color.
Shut off the heat and allow the meringues to cool to inside the oven until they reach cool room temperature, no warmer than 70°F (21°C). The timing will vary depending on the oven's age and design, but expect between 3 to 5 hours; cooling can also be done overnight. In either case, should the meringues still feel tacky and soft after cooling, return the oven temperature to 225°F and bake another hour, before cooling to room temperature once more.
Coloring the Meringues: Once the meringues have cooled, lightly dust each tray with a high-fat cocoa powder, whether natural or Dutch. Next, use your fingers to rub the cocoa powder into the caps and stems, until each has darkened to a rustic brown. Repeat as needed or as desired to achieve whatever coloration you like. As a rule, the mushrooms tend to look more realistic when the caps are darker than the stems. Cover the caps and stems tightly with plastic or transfer to an airtight container, until needed, up to one week at cool room temperature. Please bear in mind that if the container is not truly airtight, the meringues may turn soft and tacky over time.
Assembling the Mushrooms: Temper the chocolate according to whichever method you prefer (see our complete guide to tempering). Spread a small quantity of tempered chocolate onto the bottom of a mushroom cap, then dip the very tip of a mushroom stem into the chocolate as well, and join the pieces together, gently twisting the stem against the cap to secure. Arrange the assembled mushroom upside down on the empty baking sheet, pressing the stem firmly into the cap if it seems unstable.
Continue until all the mushrooms have been assembled; if needed, stems that jut out at odd angles can be balanced against the rim of the baking sheet or against the cap or stem of another mushroom. Don't worry if the stems shift or lean slightly to one side, as this will only give the mushrooms a more natural appearance in the end, but do re-adjust any stems that fall over altogether.
When the chocolate has hardened, transfer the mushrooms to an airtight container until needed (the mushrooms can be held up to 1 week at cool room temperature). As the mushrooms will soften over time in a humid environment, it's best to keep them in the container as long as possible, bringing them out to garnish a Yule log at the last possible moment, rather than in advance. How long the mushrooms will stay crisp and dry will vary depending on relative humidity. In dry conditions, they may keep well for several hours; in humid environments (particular in a kitchen with a stovetop in use for boiling or simmering), they may begin to soften in less than an hour.
Troubleshooting: While the approximate cooking times for the water bath are estimations and will naturally vary from kitchen to kitchen, substantially missing the mark in terms of timing indicates heat levels that are vastly too high or low. When the meringue cooks much too fast, it is prone to scrambling, regardless of how thoroughly the bowl is scraped, resulting in a lumpy texture and eggy flavor. When the meringue is cooked too slowly, excess evaporation will dry the meringue, making it grainy and dense. In either event, adjusting the heat as needed will prevent the issue from arising in the first place.
Chocolate that has been melted but not tempered (or chocolate that has been badly tempered) may fail to set at room temperature. In this case, cover the tray of assembled mushrooms in plastic, and refrigerate until the chocolate hardens. Transfer to an airtight container, and refrigerate until needed (up to one week).
For the best color and flavor, dust the meringues in a high-fat cocoa powder; the low-fat styles sold in most supermarkets won't do this dessert any favors. See our guides to buying the best natural cocoa powders and buying the best Dutch cocoa powders for more information on what sets this style apart, as well as how to find a brand that's right for you.
The tempered chocolate used to "glue" the caps and stems together is also a major source of flavor for these meringue cookies, so be sure to use a brand whose flavor you love. In most supermarkets, some great options can be found in the snack or candy aisle, rather than the baking department. See our round-ups of awesome supermarket dark chocolate bars and the best supermarket milk chocolate bars for some of our favorite nationally available brands.
Make-Ahead and Storage
After dusting and buffing with cocoa, the meringue mushroom caps and stems will keep in an airtight container for up to one week at cool room temperature. After assembly, the meringue mushrooms can be kept in an airtight container for up to one week at cool room temperature. In both cases, the meringues will quickly turn tacky and soft in containers that are not truly airtight.
|Nutrition Facts (per serving)|
|Amount per serving|
|% Daily Value*|
|Total Fat 1g||2%|
|Saturated Fat 1g||4%|
|Total Carbohydrate 14g||5%|
|Dietary Fiber 0g||1%|
|Total Sugars 13g|
|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.|