Italian meringue buttercream is the gold standard of professional frostings: silky smooth, barely sweet, and stable enough to hold up in warm climates where American buttercream falls apart. It is the frosting I reach for on every wedding cake and tiered cake because nothing else comes close to that light, creamy finish without the sugar overload.
Quick Glance: Italian Meringue Buttercream
- Recipe Name: Italian Meringue Buttercream
- Why You'll Love It: The most stable and least sweet buttercream you can make - silky smooth, heat-resistant, and perfect for professional cakes and warm climates
- Time and Difficulty: 40 minutes / Intermediate
- Main Ingredients: Egg whites, granulated sugar, water, unsalted butter, vanilla
- Method: Hot sugar syrup streamed into whipped egg whites, finished with butter
- Texture and Flavor: Light, silky, and creamy with a delicate sweetness and rich buttery finish
- Quick Tip: The meringue must be completely cool before you add the butter. If it's too warm, the butter will melt, and the whole thing will look soupy
Jump to:
- Quick Glance: Italian Meringue Buttercream
- Why This Recipe Works
- Italian Meringue Buttercream Ingredients
- How To Make Italian Meringue Buttercream Step-by-Step
- Batter & Frosting Calculator
- Cake Batter and Frosting Calculator
- Cups of Batter Needed
- Cups of Frosting Needed
- Common Mistakes To Avoid
- Italian Meringue FAQs
- More Frosting Recipes To Try
- Watch: How To Decorate A Cake Step-by-Step
- Recipe
Why This Recipe Works
Italian meringue buttercream is more stable than other meringue-based buttercreams like Swiss-meringue buttercream because of what happens to the egg whites when the hot syrup hits them. Sugar cooked to 240°F has lost most of its moisture through evaporation, concentrating the sugar to a very high level. When that hot syrup streams into whipping egg whites, two things happen simultaneously: the heat partially pasteurizes the egg whites, and the concentrated sugar bonds into the protein foam, creating a structure that is far more rigid and heat-resistant than what you get from Swiss meringue buttercream, which only heats egg whites to around 160°F.
The reason Italian meringue buttercream is also the least sweet is that the sugar is dissolved into the egg white foam rather than sitting in a base of powdered sugar. There's no confectioners' sugar in this recipe at all, which means no starchy aftertaste and no grittiness.
When you whip butter into the cooled meringue, the fat droplets from the butter become physically trapped within the protein network of the meringue foam, creating a true emulsion. This is why the buttercream can be rewhipped after refrigerating or freezing. The protein structure rebuilds as it returns to temperature.
Italian Meringue Buttercream Ingredients
You only need six ingredients to make Italian meringue buttercream, but the quality and temperature of each one matters. Here's what you need and why it works.
Fresh egg whites provide the foam structure that makes Italian meringue buttercream so stable. Fresh egg whites are strongly preferred over pasteurized carton egg whites because the heat treatment used to pasteurize them can partially damage the proteins, making them harder to whip to stiff peaks. If carton egg whites are all you have, make sure they are at room temperature and be prepared to whip them significantly longer than usual.
Granulated sugar is cooked with water to create the hot syrup that stabilizes the meringue. The sugar must reach exactly 240°F (soft ball stage) so that enough moisture has evaporated and the sugar concentration is high enough to set the foam properly. Under-cooking the syrup results in a soft, unstable buttercream that won't hold its shape. Do not substitute powdered sugar here since the recipe depends on the syrup-making process.
Water is combined with the sugar to help it dissolve and cook evenly into a syrup. It fully evaporates during the cooking process and is not present in the finished buttercream.
Unsalted butter is whipped into the cooled meringue to create the final buttercream. It must be softened to room temperature, not melted, and not cold. Softened butter has the right fat crystal structure to emulsify smoothly into the meringue. Unsalted butter is used so the salt level in the recipe can be controlled precisely. For a more stable buttercream in very high heat environments, you can substitute up to half the butter with solid vegetable shortening, which has a higher melting point than dairy butter.
Salt enhances and balances the flavor of the buttercream. Without it, the buttercream can taste flat and one-dimensional. Use a small amount since it should not be detectable as saltiness, only as depth of flavor.
Vanilla extract is the primary flavoring in this recipe. Use a high-quality pure vanilla extract or vanilla bean paste for the best flavor. You can substitute any flavoring you prefer, including almond extract, lemon emulsion, freeze-dried fruit powder, or espresso powder.
How To Make Italian Meringue Buttercream Step-by-Step
Before you start, make sure your butter is fully softened and your equipment is completely grease-free. Those two things alone will determine whether your buttercream comes together perfectly or gives you trouble.
- Wipe down the bowl of your stand mixer and whisk attachment thoroughly with lemon juice or white vinegar and a clean paper towel. Any trace of grease or fat will prevent your egg whites from whipping up properly. The bowl should feel completely clean and slightly tacky.
- Add your egg whites to the bowl of your stand mixer with the whisk attachment. Do not start whipping yet.
- Combine the sugar and water in a medium saucepan and stir just until the water has distributed evenly through the sugar. Place the lid on the pan and bring to a boil over medium-high heat.
- Keep the lid on for 3 to 4 minutes after it reaches a boil. The steam trapped inside will wash any sugar crystals off the sides of the pan, which prevents the syrup from crystallizing and turning grainy later.
- Remove the lid and carefully insert your candy thermometer. Continue cooking over medium-high heat without stirring until the thermometer reads 235°F. The syrup will be clear and bubbling steadily.
- When the syrup hits 235°F, turn your stand mixer on high and begin whipping your egg whites with the salt to soft peaks. You want them to reach soft peaks at the same time the syrup reaches 240°F, so the timing works out almost perfectly if you start at 235°F. Soft peaks means the whites are foamy and bright white but the tip curls over gently when you lift the whisk.
- When the syrup reaches 240°F, reduce the mixer to low speed. With the mixer running, slowly pour the hot syrup in a thin, steady stream down the side of the bowl between the whisk and the bowl wall. Pouring it directly onto the whisk will cause it to splatter and harden on the sides of the bowl. The mixture will immediately increase in volume and turn glossy white.
- Increase the mixer speed back to high and whip to very stiff, glossy peaks. To cool the meringue down faster, wrap an ice pack or bag of frozen vegetables against the outside of the bowl with a kitchen towel. The meringue needs to reach room temperature. You should be able to hold your hand against the side of the bowl comfortably with no warmth. This usually takes 10 to 15 minutes of whipping.
- Once the meringue is completely cool, reduce to medium speed and begin adding the softened butter two tablespoons at a time, waiting a few seconds between additions. The mixture may look curdled and soupy at this stage. This is completely normal. Keep whipping and it will come together.
- Once all the butter is incorporated, add the vanilla and increase to high speed. Whip for 10-15 more minutes until the buttercream is light, fluffy, and completely smooth with no trace of a buttery taste. It should hold a stiff peak and have a silky sheen.
Add food coloring now if desired, mixing on low until fully incorporated.
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Cups of Batter Needed
8 cups
Cups of Frosting Needed
5 cups
Note: measurements are estimated based off the vanilla cake recipe using standard US cake pans and sizes. Measurements used are for 2" tall cake pans only. Your results may vary. Do not overfill cake pans above manufacturer's recommended guidelines.
This recipe makes 8 cups of frosting, enough to frost and fill a two-layer 8-inch cake or frost about 24 cupcakes. Store leftovers in an airtight container in the fridge for up to 2 weeks or freeze for up to 6 months. Bring to room temperature and rewhip before using.
If you love a buttercream that pipes cleanly, holds its shape, and doesn't taste like a bag of powdered sugar, this is your recipe. Try it on my vanilla cake for a combination that's been a reader favorite for years.
Common Mistakes To Avoid
Starting with any grease in the bowl. Fat is meringue's worst enemy. Even a small amount of grease from butter, oil, or an unwashed bowl will prevent the egg whites from whipping at all. Always wipe down your bowl and whisk with lemon juice or vinegar before starting.
Adding the butter when the meringue is still warm. This is the most common reason Italian meringue buttercream fails. If the meringue is even slightly warm when the butter goes in, the butter melts rather than emulsifies and you end up with a soupy, broken mess. Be patient. The meringue must be fully at room temperature before you add a single piece of butter.
Under-cooking the sugar syrup. If your syrup doesn't reach 240°F, the sugar concentration won't be high enough to stabilize the foam. The resulting buttercream will be soft, unstable, and prone to weeping. Always use a reliable candy thermometer and confirm the temperature before pouring.
Panicking when it looks curdled. Almost everyone's Italian meringue buttercream goes through a broken, soupy, or curdled-looking stage when the butter first goes in. This is not a failure. Keep whipping on medium-high and the emulsion will come together within a few minutes and the texture will turn silky and smooth.
Using butter that is too cold or too warm. Cold butter breaks into chunks that don't incorporate smoothly. Melted butter causes the buttercream to collapse. Butter should be softened to the point where it holds its shape but gives easily when you press your finger into it, similar to the texture of soft clay.
Italian Meringue FAQs
Both are made with egg whites and butter, but the process is different. Swiss meringue buttercream heats the egg whites and sugar together over a double boiler to about 160°F before whipping, while Italian meringue buttercream uses a hot sugar syrup cooked to 240°F that streams directly into the egg whites as they whip. The higher temperature of Italian meringue buttercream creates a more stable foam structure and a more heat-resistant final buttercream. Italian meringue buttercream is generally considered the more advanced and more stable of the two.
The curdled appearance happens when the butter is slightly cooler or warmer than the meringue and the fat and water temporarily separate before fully emulsifying. Keep whipping at medium-high speed and it will come back together into a smooth, silky texture within a few minutes. If it looks soupy rather than curdled, the meringue was still too warm when the butter went in. Refrigerate the bowl for 10 to 15 minutes and rewhip.
Yes. Add gel food coloring in the final step after all the butter and flavoring are fully incorporated. Use gel or paste colors rather than liquid food coloring, as liquid can thin the buttercream slightly. Add a small amount at a time and mix on low until you reach your desired shade. Colors will deepen slightly as the buttercream sits.
Italian meringue buttercream keeps at room temperature for 2 to 3 days, in the refrigerator for up to 2 weeks, and in the freezer for up to 6 months. Before using refrigerated or frozen buttercream, bring it fully to room temperature and rewhip in your stand mixer until it returns to its original light, smooth consistency. It may look broken at first but keep whipping and it will come back together.
Fresh egg whites give the most reliable results. The heat treatment used to pasteurize carton egg whites can damage the proteins, making them harder to whip to stiff peaks. If fresh eggs are not available, carton egg whites can work. Make sure they are fully at room temperature and be prepared to whip them longer than you would fresh whites. Results can vary by brand.
Replace up to half the butter in the recipe with solid white vegetable shortening. Shortening has a significantly higher melting point than butter, which gives the buttercream more resistance to heat and humidity. The texture will be slightly less silky and the flavor less rich than all-butter, but the stability improvement in warm climates is significant.
Yes. Italian meringue buttercream takes on added flavors very well. Popular options include almond extract, lemon or orange emulsion, espresso powder dissolved in a teaspoon of hot water, melted and cooled chocolate, fresh fruit puree, or freeze-dried fruit ground into a powder. Add your flavoring in the final mixing step in place of or in addition to the vanilla.
More Frosting Recipes To Try
Watch: How To Decorate A Cake Step-by-Step
Before you start decorating, watch the video below where I show you every step of decorating a cake from start to finish. Seeing the process in action makes it much easier to follow along
- Liz Marek.
Recipe
Equipment
- Stand mixer with the whisk attachment
- Candy Thermometer
Ingredients
- 16 ounces granulated sugar
- 8 ounces water
- ¼ teaspoon salt
- 8 ounces egg whites (about 8 large egg whites separated from the yolk)
- 24 ounces unsalted butter softened
- 2 teaspoon vanilla extract
Instructions
- On the stovetop, mix together the water and sugar, cover with a lid and bring to a boil on medium-high heat.
- Keep the lid on the pot for 3-4 minutes while the mixture simmers to ensure all the sugar granules are dissolved, otherwise, your sugar can get gritty and crystalize. DO NOT MIX.
- Remove the lid, insert the candy thermometer carefully and continue cooking on medium-high until the syrup reaches 240° F.
- When the sugar solution is at about 235° F, begin whipping the egg whites on high speed. Add the salt to the egg whites.
- When the egg whites reach soft peaks, pour the sugar solution in a steady stream on to the whipping whites while mixing on low speed.
- Continue whipping the egg/sugar mixture until it reaches stiff peaks. I wrapped an apron around my bowl with an ice pack to help the meringue cool down faster. You can also cool the meringue by scooping it out of the bowl and placing it into the fridge for 15 minutes.
- Once the meringue is cooled, whip in soft butter and vanilla until the buttercream is light and fluffy and no longer has a butter taste. This can take from 10-15 minutes. If it looks curdled and watery just keep whipping. It will come together I promise.
Video
Notes
- Make sure your sugar syrup reaches exactly 240°F. Under-cooking it will result in a soft, unstable buttercream that won't hold its shape.
- Keep the lid on the pot for the first few minutes to prevent sugar crystals from forming on the sides of the pan.
- Begin whipping your egg whites when the syrup hits 235°F so they reach soft peaks right as the syrup is ready.
- The meringue must be completely cool to room temperature before adding butter or the buttercream will become soupy.
- Use softened but not melted butter. It should hold its shape but give easily when pressed.
- If the buttercream looks curdled or soupy, keep whipping. It will come together.
- To store, refrigerate for up to 2 weeks or freeze for up to 6 months. Bring to room temperature and rewhip before using.
- For extra stability in warm climates, replace up to half the butter with solid vegetable shortening.
Anita says
This recipe went perfectly until I added the butter. The mixture looks like the butter isn’t incorporating (little specks of butter in the meringue). Any suggestions?
Elizabeth Marek says
Keep whipping.
Sherlyn says
Hi, I've previously tried SMBC which requires the egg whites to be heated up to 70 degrees celsius so it is safe for consumption. Is it not required for IMBC or does the heated sugar syrup help in some way? Thank you!
Elizabeth Marek says
The boiling sugar pasteurizes the egg whites in this case
Jules says
Novice baker here. As I’m a novice I was panicking through the beating process, wondering if it was going to come together.
It did but it took a power of beating!
And it’s amazing!
Tiffany says
This recipe was great! So easy to follow and my buttercream came out great! I ended up whipping the final product for about 10 minutes.
Kerri says
If I made it all perfectly then added the butter and and it fell because the meringue was deceptively not chilled enough.....is there any way to fix it or do I need to start over?
Elizabeth Marek says
Just keep mixing! It will fluff back up
Rachel says
Ho this is the first time I'm making it and I was really excited, but when I added butter it turned into liquid. I've been whipping it for several minutes but nothing changes. I am so bummed now. Today is my mother's birthday and I was making this for her 🙁
Elizabeth Marek says
Sounds like you didn't let your meringue cool down
Jay says
Hi, I followed the instructions but the result is so greasy and taste like butter. Can you give me a tips of how to avoid this result? Really need to know how to do this perfectly with the perfect taste. Thanks
Elizabeth Marek says
Keep whipping. Italian meringue is very light and fluffy and not greasy.
Katie says
Im attempting to make an anti gravity beer cake for a friends birthday. Ive just nealy had a heartattack when i added butter and it started splitting. Fortunately i had read through comments already and kept whipping and it came together.
Even though i am a bit heavy handed, i added a tiny bit of violet to get a better white colour and that also worked.
I also made LMF for the first time and had to mix colours which ALSO turned out great.
The cake has a crumb coat of ermine frosting and is in the fridge before the fondant is going on and the IMBC goes on top as beer foam.
Im slightly nervous that it has all come together so well so far. I will probably drop it ha ha ha.
Thanks for the great recipes as always!
Brandy Peiffle says
Thank you for this amazing recipe. I do have to ask what the brand of mixer you are using. I need one! 🙂
Elli says
Thank you for sharing Liz!
I attempted a recipe like the above, with pasteurized egg whites and cream of tar tar. Got to peaks and everything was looking so good. UNTIL....
I added melted chocolate and a tbspn of espresso with hot water to the mix. The minute I did that it deflated.
I thought it would be ok once I added the butter, but nope it turned into soup and even separated. Put it in the fridge for 20 mins whipped it up and it still looked like curdled soup.
Put in the fridge for longer 1 hour and once I took it out it looked like separated and even bled caramel.
I tried everything from whipping it for longer at high speeds, even added more sugar and icing sugar to save it! LOL you can imagine that did nothing! A day later and it’s still looking curdled, separated, bleeding caramel and melts soooo fast as soon as it’s out of the fridge.
It was a HOT mess and I’m still laughing at how bad it turned out. I realize now I perhaps did not wait till it was cool enough to add the butter. It was also a really warm day here in Toronto. I also probably should have used cocoa powder instead.
What else did I do wrong? Help! I want to learn not to do that again! LOLOL
Thank you!
Elli
Elizabeth Marek says
Don't add any chocolate or espresso until the buttercream is completely done (meringue cooled and butter added).
Jennifer Berta says
Can you add melted chocolate instead of cocoa powder? If so, how much and what type?
Elizabeth Marek says
You could but you might get unmelted chunks of chocolate in the meringue. Adding room temperature ganache is safer. You can add as much as you want.
Jenna says
I’ve made this perfectly several times but this time I have tiny lumps in my merengue after I add the syrup and still after I added the butter. Any suggestions or ideas what I did wrong? Thank you for all your delicious recipes!
Elizabeth Marek says
It could be that your syrup is hitting the side of the bowl or hitting the whisk. The syrup has to be carefully drizzled between the mixer and the side of the bowl while mixing to avoid lumps.
Anna says
Hi... Can I use IMBC in between my cake layers as well ad frost it with a final coat.?
Elizabeth Marek says
Yes you can
Kathy says
Does this icing crust? I’m wanting to paint on it. It will be outdoors for a wedding in July and I need something stable also. What kind of icing would you recommend?
Elizabeth Marek says
No it doesn't crust but it is very stable in hot weather
Courtney Peters says
The meringue was 100% perfect, and cool to the touch. I transferred it back into the mixing bowl I added the tiniest chunk of butter and it turned to complete liquid. I tried to bring it back but there was absolutely no chance. Do you know what happened or how to fix it?
Elizabeth Marek says
If the butter melted then your meringue was not cool.