FrostingsHard

Silky Swiss Meringue Buttercream

The buttercream that ruins all other buttercreams for you. Glossy, barely-sweet, and so silky it almost feels like custard — the standard for clean wedding-cake finishes and decorator-grade piping.

Prep
35 min
Bake
5 min
Serves
24 cupcakes
Difficulty
Hard

Method

  1. 1

    Wipe the bowl of your stand mixer and the whisk attachment with a little white vinegar or lemon juice on kitchen paper. Any trace of fat or yolk will stop the meringue whipping properly.

  2. 2

    Set a saucepan with about 5cm (2 inches) of water on a low heat to a bare simmer — do not let it touch the bottom of the bowl when you place it on top.

  3. 3

    Place the egg whites, sugar, and salt directly in the stand mixer bowl. Whisk by hand to combine, then set the bowl over the simmering water. Whisk slowly and constantly, scraping the sides, until the sugar is completely dissolved and the mixture reaches 71°C (160°F) on a digital thermometer — usually 4–6 minutes. To test without a thermometer, rub a little between your thumb and forefinger; you should feel no grit at all.

    Heat to 71°C05:00
  4. 4

    Carefully transfer the bowl to the stand mixer fitted with the whisk attachment. Whisk on medium-high speed until the meringue is glossy, holds stiff peaks, and the bowl feels cool to the touch — usually 8–12 minutes. Do not rush this step. If the meringue is even slightly warm when you add the butter, the buttercream will go soupy.

    Whip to stiff peaks10:00
  5. 5

    Switch to the paddle attachment. With the mixer on medium-low, add the butter one tablespoon-sized cube at a time, allowing each cube to disappear before adding the next. The meringue will deflate noticeably and may look curdled or soupy partway through — this is completely normal.

  6. 6

    Once all the butter is in, increase the speed to medium-high and beat for a final 3–5 minutes. The mixture will pull together into a thick, silky, almost mayonnaise-textured buttercream. Add the vanilla and beat for 30 seconds more.

    Bring it together04:00

Baker's Notes

  • Soupy and refusing to come together? The meringue or the butter was too warm. Refrigerate the bowl for 15 minutes, then re-whip on medium-high — the cold will firm the butter and the buttercream will tighten.
  • Curdled and looking like cottage cheese? The butter is too cold. Take a quarter of the buttercream out, microwave it in 5-second bursts until just-melted at the edges, and add back to the bowl while whipping. Two minutes of whipping will smooth it out.
  • Egg whites: 120g of liquid egg whites from a carton works perfectly — make sure they are pasteurised, not just refrigerated. Powdered egg whites also work; reconstitute according to packet instructions.
  • Flavour variations: replace the vanilla with 60g cooled melted dark chocolate, the seeds of 1 vanilla pod, 60g freeze-dried fruit powder (raspberry, strawberry), or 30ml strong espresso. Add at the end on low speed.
  • Yield: covers and fills a 23cm two-layer cake or pipes onto 24 cupcakes. Stable enough for warm-weather wedding cakes provided it stays under 24°C.
  • Storage: airtight in the fridge for up to 1 week or frozen for 3 months. To re-use, bring fully back to room temperature and re-whip on medium-high for 3–5 minutes — it will look broken at first and then come back together.

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Published 2 May 2026·Bo