Swiss Meringue Buttercream

I use Swiss Meringue Buttercream (or SMB for short) a lot.  You have heard me go on and on about it as my weapon icing of choice, so I thought it was about time it got a post of its own to share the variations and tricks I have learned along the way.  You have seen me use it as the filling in my Purple Corset Cake and Bûche de Noël, and for piping beautiful decoration on a wedding cake, cupcakes and my very first ombre petal cake.  There have certainly been a few disasters along the road, with a batch or two thrown away, but regardless it is wonderful to work with, and when it is done right it looks, and tastes, exquisite.

There are essentially three types of meringue making methods which differ by how and when the sugar is added:

• Swiss Meringue = Heating the egg whites and sugar in a double boiler and then whisking until it has completely cooled again
• Italian Meringue = Making a sugar syrup and pouring it into egg whites which have been partially whisked and again whisking until cool (this is the method I use for my macarons)
• French Meringue = Whisking the egg whites until soft peaks and then gradually adding the sugar, whisking until firm peaks.  This is the uncooked method and the basis for pavlova.

Once you make the meringue, you can use it as it to top a lemon meringue tart or to ice cakes or cupcakes as is.  When you add the butter is when it becomes the buttercream (logical, I know).

So onto the nitty-gritty.

Swiss Meringue Buttercream – The Method

The recipe I use is from Martha Stewart and the variations I have made include chocolate, rose water and creme de menthe (mint) plus you can make it any colour your heart desires.  To start, gather the egg whites, sugar, butter and a little vanilla (if you are making the standard version).

Place the egg whites and sugar in a clean bowl over a pot of simmering water.  Stir constantly until it becomes hot to the touch (most websites recommend 71°C/160°F ) and the sugar has dissolved.  To check this, rub a small amount between two fingers and it should not feel gritty if all of the sugar has dissolved.

Transfer the mixture to a clean bowl of an electric mixer and start to whisk on medium speed so that hot liquid doesn’t fly everywhere.  Once you have soft peaks increase the speed until you have firm, glossy peaks.  You will need to continue to whisk until the bowl is neutral/cool to the touch.

Once the meringue is cool enough, it is time to add the butter.  It is imperative the meringue is cool otherwise the butter will just melt and you will have a mess on your hands.  Some switch to the paddle attachment on the mixer at this point but I like to keep the whisk as meringue is a pain in the behind to get off the whisk and it is much easier to scrape the excess off once the butter has been added.  Add the softened butter, a piece or two at a time and whisk on a medium-high speed until the butter in corporate.

The mixture will go through a couple of stages and don’t freak out.  There will be a liquid stage (might look a little more runny than this)…

and a curdled stage.

I must admit, the first time I made this I knew it would curdle but it still spins you out.  But continue to whisk as in a few more minutes it will come together.

Once the mixture is smooth and you can no longer see any traces of butter add your flavouring (e.g. vanilla, creme de menthe, rose water) and whisk briefly until distributed.  If you would like to colour your buttercream, also do it at this stage.

Switch to the paddle attachment and mix on the lowest speed for at least 5 minutes as this will eliminate any air pockets that have appeared and give you that nice, billowy buttercream you are after.

Swiss Meringue Buttercream – The Variations

You can flavour and colour SMB to whatever your heart desires and if you are lost for inspiration, how about Oreo, caramel, espresso, honey and cinnamon, brown sugar or raspberry.

I have made a chocolate version by adding cooled melted chocolate towards the end and folding it through before switching to the paddle attachment.

Instead of using vanilla, you could use creme de menthe, or mint extract for a refreshing version.

Tint the SMB with any colour of the rainbow, or different shades of the one colour if you are going for an ombre effect like I did in my Peach Ombre Petal Cake.

Swiss Meringue Buttercream – Troubleshooting and FAQ’s

What do I do if my SMB starts to split as I am piping?

Now this has happened to me a couple of times, namely due to the SMB setting because I live in a cool area and then when it warms up in my hands as I am piping the texture is all kinds of wrong and you get little pools of clear or coloured liquid (you might be able to make it out in the picture below).

This has happened before and in the past I have started another batch.  On this particular occasion, I had been piping for over 3 hours, didn’t have enough ingredients for another batch and it was late at night and cold (whine much?).  So I consulted Mr Google and lo and behold a solution to my problems.  By microwaving a small amount of the buttercream (general rule is about 1/3 of the mixture but I used a little less for my first attempt) for 10-15 seconds, and then mixing it through the rest, the SMB was restored to its former glory.

I will never need to start again… fingers crossed.

There is some SMB leftover, will it keep in the fridge or freezer?

Yes it will, but as a general rule only 3-5 days in the fridge, or up to 6 weeks in the freezer.  Let it come to room temperature and then mix with the paddle mixer to restore it.  If that doesn’t work, use the above method.

Can you use the egg whites in the carton that have been pasteurised?

Given how all sorts of problems can come from bad eggs, if you want to be extra safe for any pregnant women or elderly folk who may be consuming your cake, you can use the carton egg whites.  I have used them once before and I think because I was all flustered and didn’t think it came out as it should have, I didn’t end up using the batch but I think if I did the microwave trick it would have been fine.  I will be giving it another attempt as it is also can save on wastage if you do not end up using the egg yolks in something else.  However, if you heat your eggs to 71°C/160°F you should be OK.

If it is hot outside, will my SMB hold it’s shape?

Probably not.  If your cake is going to be outside on a really warm/hot day, it probably would be best to only bring it out at the last minute as you may find that the buttercream starts to lose its texture and as the butter melts it can look quite greasy.

Further reading

If you haven’t had enough of this lengthy post, feel free to read a bit more about SMB on the following websites:

• Sweetapolita – Swiss Meringue Buttercream Demystified
• Bakers Royale – Baking Basics: How to make Swiss Meringue Buttercream Frosting
• Whisk Kid – How to Make Swiss Meringue Buttercream

Print Recipe

Swiss Meringue Buttercream

Adapted from Martha Stewart

Course

Icing/Frosting

Servings

cups

Ingredients

• 2 1/2 cups caster sugar
• 10 large egg white(s)
• 907 g unsalted butter cubed and softened
• 2 tsp vanilla extract

Course Icing/Frosting Servings cups Ingredients 2 1/2 cups caster sugar 10 large egg white(s) 907 g unsalted butter cubed and softened 2 tsp vanilla extract

Instructions

1. Place the sugar and egg whites into a heat proof bowl and place on top of a pot of simmering water.
2. Stirring constantly, bring the mixture to 71°C/160°F and ensure all of the sugar has dissolved by rubbing a small amount between two fingers (it should not feel gritty).
3. Transfer the mixture to the bowl of an electric mixer fitted with the whisk attachment and whisk on medium speed until soft peaks. Increase speed to high and whisk until thick glossy peaks are formed and the bowl is neutral/cool to the touch.
4. A couple of pieces at a time, add the softened butter and continue to whisk until all of the butter has been incorporated.
5. Add the vanilla extract and whisk to distribute. Any colouring or other flavouring should be added at this point (refer Notes).
6. Switch to the paddle attachment and beat on low speed for at least 5 minutes to remove any air pockets.

Recipe Notes

Variations: Chocolate - Mix in 200g melted, and cooled, chocolate at step 5. Mint - Omit the vanilla extract, and replace with 3 tbsp creme de menthe or mint extract. Rose - Reduce the vanilla extract to 1 tsp and add 1-2 tsp of rose water.