No Thanks
Keep In Touch With

Sign up and we'll send inspiration straight to you.

Martha Stewart takes your privacy seriously. To learn more, please read our Privacy Policy.

Lemony Swiss Meringue Buttercream

Use this buttercream to frost "Whisk Kid" blogger Kaitlin Flannery's colorful Rainbow Cake.

  • Yield: Makes enough for one 9-inch-round six-layer cake
Lemony Swiss Meringue Buttercream

Source: The Martha Stewart Show, Episode 5128


For the Filling and Crumb Coat

  • 9 large egg whites
  • 1 3/4 cups sugar
  • 2 cups (4 sticks) unsalted butter, cut into small pieces, room temperature
  • 2 teaspoons pure lemon extract

For the Frosting

  • 5 large egg whites
  • 1 cup sugar
  • 1 cup (2 sticks) unsalted butter, cut into small pieces, room temperature
  • 1 teaspoon pure lemon extract


  1. Make the filling and crumb coat: Cook egg whites and sugar in a small saucepan over medium heat, whisking constantly until sugar is completely dissolved. Transfer to the bowl of an electric mixer fitted with the whisk attachment; mix on high speed until mixture is room temperature. With the mixer on medium-low, add butter, one piece at a time, mixing well after each addition.

  2. Remove whisk attachment and switch to paddle attachment. Increase speed to high and beat until buttercream comes together, about 5 minutes; beat in lemon extract.

  3. Make the frosting: In a clean saucepan and bowl of an electric mixer, repeat process in step 1.

Reviews (26)

  • mkyun 3 Aug, 2014

    I've never made meringue before. And before I started I debated using this recipe because of the negative reviews. But this came out beautifully! Followed the directions to a tee. There were times where I questioned myself... "is the sugar completely dissolved?" "is my butter warmer than room temperature?" "how long to I let it mix?" At one point I started to worry about the watery consistency...but give it time. It does come together.

  • mrangone 29 Jun, 2013

    Por favor alguien me puede decir cuanto pesa cada barra de mantequilla que se usa en esta receta?. Necesito saber por que en Argentina hay barras de 100 grs y de 200 grs. Gracias!!!

  • tckt 15 Feb, 2013

    This buttercream is fabulous. It is really important that you heat the egg whites and the sugar over a water bath. It needs to reach about 115 degrees and the sugar all needs to be melted. I would use the metal electric bowl and then transfer it right to the stand mixer. Beat really well until soft peaks develop, long past room temperature. Cold butter cubed a little bit at a time and your frosting will be fabulous.

  • freecreditscorefree 9 Feb, 2013

    A photo would nice to have for this recipe ... (

  • Lightpeace 23 Sep, 2012

    Not sure why so many negative reviews. Came out perfect & delicious. TIPS: 1. If you get even the slightest hint of yolk in your whites, game over. 2. If you use a hand-mixer instead of a standing mixer, you may have to beat a lot longer. Use the right mixer attachments (whisk and flat), too. 3. Beat 'til frothy peaks b4 adding butter (not just "until room temp"). 4. Don't overcook egg-sugar mix; just gently heat for 2-3 mins, med-high so sugar dissolves. If done right, whole recipe = 10 mins.

  • julierichey 21 Sep, 2012

    I agree with the others re: this buttercream meringue. If my frosting turns out it will be a minor miracle - I've been beating it for more than 10 minutes. More detailed instructions on this tricky process would be very helpful - if not essential. Warnings, like "be sure not to... " and "bring the egg/sugar mixture on the stove to ___ degrees could be added. Other recipes give a temperature reading - I'm not sure if I under or over-cooked the meringue. Pretty cake though!

  • jjseymour 14 Sep, 2012

    I just made the cake for the second time and the frosting for the first time. You weren't kidding when you said it takes a long time for the buttercream to come together! Phew! But it came out beautifully and I'm so excited to serve this at my friends' wedding tomorrow! :) Cheers!

  • lindsie79 4 Aug, 2012

    I was so disappointed with this recipe. The buttercream is revolting. Mine came up yellow and tastes as though you're eating a stick of butter with sugar on it. It was so greasy and revolting I abandoned the icing part way through the layers and made the fluffy frosting from the Australian Woman's Weekly cakebook. It tastes so much better and is a pure white.

  • miriam antonello 2 Aug, 2012

    Wish I'd read the reviews before I attempted this cake for a special 30th birthday party. Apart from the quantities which are so vague, what the heck is a cup measurement or a stick of butter for God's sake? The frosting was a complete disaster & so after buying 14 eggs!!! I'm now debating what the heck to do with the sloppy yellow mess which will probably end up in the bin.

  • christiemstewart 25 Jul, 2012

    AWESOME! Followed directions exactly... came out perfect! Best Buttercream filling and frosting ever! Not sure why everyone is having such difficulty. I used a boiling bath to wisk the sugar/eggs... maybe that will help others? Defiantly savings this recipe for future use!!!!

  • crabble_sac 3 Jul, 2012

    for ALL you newbies/random hobbyists*likeme*, READ this website first ( ).

    I spent 2 hrs making this buttercream icing (only the crumbcoat&filling is enough for all of the cake, even had extra).

    TIPS: use 1-3 extra egg white or so if u use SMALL EGGS (or dunno its size). beat the egg after sugar dissolves REALLY well; put the butter SMALL and SLOW; BEAT a lot!!

  • joy hillmanz 30 Jun, 2012

    Initially I thought this was NOT working - beat it for almost an hour. Gave up and set it aside. Then made the cakes and measured the butter differently - realised 1 cup of butter is actually 200g and I'd not used enough in the icing! Went back to beat again, adding another 100g butter (slowly) to make it 400g in total. Then it looked a bit curdled... oh no! Anyway, I changed beaters and 3 mins later.. voila! it worked!!! Yum! So make sure you use enough butter, & the result is scrummy :)

  • saf_atan 22 Jun, 2012

    I tried this recipe. In my opinion the filling and crumb coating was more than sufficient to cover the cake. A few notes for those never attempted this: whisk the egg whites until have soft glossy peaks, make sure butter is relatively cool (not stone cold) and a little at a time, and just continue beating. Initially it will be liquidy, trust me, just have faith and let it beat until it comes together. Feels like forever, it's worth the wait.

  • kristine rankin 3 Jun, 2012

    I think this was a wonderful receipe. My butter cream worked out wonderfully but I did let it whip until it formed glossy peaks, only by accident though so maybe there is some theory to this idea. Anyway apart from being pretty fiddly and long winded I found the cake turned out just great. I is a couple of heart attacks in each slice though with all the butter involved but I guess you were not meant to eat the whole cake :). Adding the grams to the receipe would help us here in AUS.

  • sarahwood5686 25 May, 2012

    For real, don't even try this. For the average person who doesn't bake as a hobby, this is way too finicky. Just do something else. I read all of the reviews and thought the end result looked so beautiful (thick and buttery) I would at least try it. I was even aware the soft peak thing. Nope, still soupy. I just don't understand it. Extremely frustrating!!!!

  • Fromage58 31 Mar, 2012

    I just made this recipe for my daughter's birthday cake (Rainbow Cake) and thought it was terrific. I followed the directions exactly and found the consistency perfect. It even tasted good! I think previous reviewers who found the texture too soupy probably didn't let the egg white and sugar mixture come to room temperature while being beaten in the mixer.

  • JessieSSS 7 Mar, 2012

    EVERYBODY BEWARE!! this recipe is an absolute horrid! i completely agree with everyone elses reviews!!! i followed instruction exactly and yes i did try to put it in the fridge to see if it would thicken but it NEVER did and stayed soupy!!

    like everyone else, i wasted heaps of money on ingredients and now have nothing to frost my mothers birthday cake which is for tomorrow!! very very dissappointed and it is very fustrating.

  • krista210 21 Jan, 2012

    To the person who spent $70 on this recipe, I suggest you find another place to do your shopping! I purchased a carton of egg whites (500g) for 3.99 and was able to make the cake and the crumb coat and filling which is all I needed to frost the entire cake as well. Add in about $6 for butter and everything else I had in my pantry as they are completely normal ingredients. I referenced another website for reserach on the icing and mine turned out great. Serving for my daughters 2nd bday tomoro!

  • kookycakes 14 Dec, 2011

    Just a suggestion for people who find their buttercream has gone 'soupy'. This happens because the butter gets too hot (either from the ambient temperature or from the friction of beating). Try putting the mixture in the fridge for 15mins and then re beating with the paddle of your mixer. It might look like scrambled eggs for a bit but them it should magically come together and go all smooth and yummy.

  • missjamie166 9 Aug, 2011

    AVOID THIS RECIPE!! I followed the instructions EXACTLY. The cake was horrible tasting when I tried the crumbs, it tasted very egg-y and unpleasant. I tried making the frosting, it never hardened. It was a soupy texture, even taking into account the last comment, about having to whip the eggwhites til they formed peaks, I did, it was still soup. I wasted $70 on ingredients, (19 eggwhites if you make the buttercream frosting too!!) and 4 hours because I had to bake the layers in shifts. NOT COOL.

  • lucysmomrocks 23 Jun, 2011

    For those that have never made a meringue buttercream before, this recipe happens to leave out a very important step. Instead of just whipping your egg white/sugar mixture until it reaches room temp. You should also whip it until it forms nice, glossy peaks. This will help allow your buttercream set and not become soupy. Very odd that this was left out of this particular recipe.

  • msmarmitelover 28 Apr, 2011

    This recipe does not work. I've done it twice now and wasted alot of ingredients. Plus, please put grams. I got the original recipe from whisk kid and she puts grams which I think are wrong.
    You have readers from abroad! Cups are so inaccurate!

  • nicole1foxy 25 Sep, 2010

    The directions are not clear for step 1. There is a crucial detail. Whip the egg whites until soft peaks form. This should be added, not just to whip until room temperature. I had never made butter cream before, and so,after failing, I looked up other recipes- and that was the problem.

  • mrsgood 23 Jun, 2010

    How many cups/ounces does this frosting make?

  • Sue2 23 Jun, 2010

    A friend made it for her adult son's birthday. Both he and her husband were full of awe when he cut into it, it was such a surprise. And they are both not easily impressed!

  • scatkin 14 Jun, 2010

    Can't wait to try Rainbow Layer Cake

Related Topics