[Updated 12/07/2026]
Swiss meringue buttercream is smooth, light and less sweet than a conventional icing-sugar buttercream. It takes a little more care than a simple frosting, but the method is straightforward once the temperatures are controlled properly.
What Is Swiss Meringue Buttercream?
Swiss meringue buttercream is made by heating pasteurised egg whites with granulated sugar, whisking the mixture into a glossy meringue and then gradually beating in softened butter. It is suitable for filling, covering and piping cakes, cupcakes, macarons and choux pastry.
Ingredients
This quantity is enough for one 6-inch layer cake or approximately 12 cupcakes.
- 150g pasteurised egg whites, at room temperature
- 225g granulated sugar
- 300g unsalted butter, softened but not greasy
- 1 teaspoon vanilla extract
- A pinch of salt
Method
1) Place the pasteurised egg whites and granulated sugar in a thoroughly clean heatproof mixer bowl. Set the bowl over a saucepan of gently simmering water, making sure the water does not touch its base.
Whisk continuously until the sugar has dissolved and a reliable food thermometer reads 71°C. Do not use touch as a substitute for checking the temperature.
2) Transfer the bowl to the stand mixer and whisk on high speed until the meringue forms glossy peaks and the bowl has cooled. This is the Swiss meringue base.
3) Reduce the mixer to low speed. Add the vanilla, salt and softened butter gradually, allowing each addition to combine before adding more.
The mixture may look curdled or loose partway through. Continue beating on high speed for approximately 5 to 8 minutes until it becomes smooth and silky.
4) Use the buttercream immediately, or refrigerate it promptly in a clean covered container. Before using chilled buttercream, allow it to soften to a workable temperature and rewhip until smooth. Follow the storage guidance supplied with the full recipe and do not rely on the old claim that it keeps for several weeks.
Troubleshooting
- Looks soupy? The mixture may be too warm. Chill the bowl briefly, then whisk again.
- Too stiff? Warm a small portion gently, add it back to the bowl and rewhip.
- Still curdled? Continue whisking. A temperature imbalance often resolves as the mixture comes together.
The buttercream can be flavoured with cocoa, fruit purée, caramel, citrus or another suitable ingredient once it is smooth.
Browse our birthday cakes for decoration ideas or see the full Swiss meringue buttercream guide.
Lots of love,
Reshmi xoxo
Hi just wondering when adding the butter do you change the attachment from whisk to paddle, just I found the whisk got very gunked up with butter and had to keep stopping it to clear? Thanks
If using the pasteurised egg whites do you still need to heat over a saucepan? This is the step that puts me off!
I finally plucked up the courage to make this Swiss meringue butter cream to top my hero sponge cupcakes.
The heating and the amount of mixing (I don’t have a stand mixer, so used an electric hand mixer) sounded a little scary but it worked out well and actually wasn’t too difficult!It’s delicious and soooo smooth. The most amazing part is no icing sugar coating your entire kitchen 😅
Would the egg whites in this recipe be considered still ‘raw’ do you think? Never use raw eggs anymore, because of the risk of salmonella contamination.
What size cake is the recipe for? Thanks
Amazing Swiss Buttercream method I’ll be adopting from now on. I even made this on a very hot day and it held so well for colouring and lots of detailed piping. Looking forward to trying again with more interesting flavour combinations.
Best buttercream ever! Made your mermaid cake followed your instructions ,turned out brilliant and your sponge is moist too!
Hey Reshmi, thanks for sharing! Once the Swiss meringue bc is in the cake does the cake need to be kept in the fridge too?
Thanks