Swiss Meringue Buttercream is awesome, but it can be so hard to make.
This is the perfect buttercream icing for piping because, as the name suggests, it contains egg whites. Egg whites are a super strong binding agent that give stability to the buttercream which would otherwise melt or split while inside the piping bag from the warmth of your hands. It’s great for eating because it’s creamy and smooth.
Traditional SMB involves whipping up a thick, fluffy meringue and then adding butter to it at precisely the right temperature, in precisely the right measure and at precisely the right time. It’s tricky because the butter will often deflate the meringue in a matter of seconds, leaving us with a rather disheartening, curdled-looking mess. Most sources say that you can just keep beating the buttercream when this happens and it will magically come together. This is true, but not reliable. And ya know, even if it is true, why put yourself through the emotional strain?
I tried to follow a traditional recipe a few times – it worked well once and also failed horribly once. Out of desperation I googled ‘“foolproof” swiss meringue buttercream’ and came across a recipe from a blogger in the US – it gives a useful scientific explanation of why the traditional method of making SMB is so hit and miss. My understanding is that the fats in the butter cause the aerated egg whites in the meringue to collapse. The butter works much better as an emulsifier with egg whites in syrup form rather than meringue form. For the full write up, see this post on Cake Paper Party – http://www.cakepaperparty.com/2014/04/foolproof-swiss-meringue-buttercream/.
While the ratio is definitely important, it is by no means set in stone – you just need to make sure the amount of egg whites used is equal to at least half the amount of butter (1:2). Extra egg whites don’t hurt but may not be necessary. The original recipe measures egg whites in weight because it uses the already separated version available in cartons. I use fresh eggs, but you can still measure in weight using a scale (or estimate – if an egg is 70g, the egg white is probably around 40g). Again, I have adapted the recipe for quantities available in Australia and changed it to metric measurements. I also added cream of tartar for peace of mind as it is commonly used for stabilising egg whites, reduced the sugar – just add more if you want it sweeter.
It’s important to note that you can do a lot with this buttercream. While this recipe calls for vanilla, I have used things like elderflower cordial, Wizz Fizz and tea to flavour it.
Firstly, make the egg white syrup. Make sure it reaches around 72 degrees. The whites will have technically cooked, but they will be free of salmonella when they reach this temperature. It’s good to be precise, but not essential. I don’t own a cooking thermometer, I usually just wait for the sugar to blend in with the egg whites because this only happens at well above 72 degrees. Also, if you’ve ever done coffee making, you’ll know how to feel for temperature! Once this is done, chuck the bowl in the fridge to cool down, but only to room temperature, so keep checking it.
While the syrup is cooling down, whip up the butter til it’s fluffy. I love the look of white buttercream, which is why I try to use a good quality butter. Organic butter is closer to white than yellow. To lighten it further, I used this Wilton white icing colour. It’s also great if you’ve added too much food colouring to something and want to undo it.
Once the syrup is at about room temperature, beat it into the butter a little at a time. When it’s all combined the buttercream should be a little sticky and springy. It should ball up slightly and pull away from the side of the bowl.
Spread or pipe in your favourite patterns. For this rose pattern, use a star tip (I used Wilton 2D) and pipe in a spiral, starting from the middle going in circles to the edge.
This amount should cover 24 cupcakes.
~ Recipe ~
- 6 egg whites (around 240g)
- 400g butter – softened
- 300g sugar
- 1 tsp cream of tartar
- 0.5 tsp of salt
- 1 tsp vanilla bean paste
- Place egg whites and sugar into a heatproof bowl along with a thermometer, over a saucepan of boiling water. Make sure the water isn’t touching the bowl above.
- Slowly whisk the egg whites and sugar until combined. Keep the syrup over the heat until it reaches around 71-72 degrees. The egg whites have just cooked but still look raw without becoming opaque.
- Take it off the heat and cool to room temp in the fridge. You’ll need to check it every now and then so it doesn’t get too cold.
- In a large mixing bowl, beat the butter until light and fluffy.
- Once the sugar and egg white syrup has cooled to about room temperature, add a little to the butter and beat until combined. Repeat until all of the syrup is used up.
- Add in the salt, cream of tartar and vanilla (or other flavour) then beat for about 1 more minute to lighten the buttercream even more.
- Use a spatula to spread onto cake or transfer into piping bag to make your favourite designs/patterns.