Italian meringue buttercream is made by creating a sugar syrup, which is used to cook whipped egg whites. This creates a firm and glossy meringue, which is easy to pipe and holds up well in warm weather.
As with Swiss meringue buttercream, it’s important to reach the correct temperature to make sure the eggs are cooked. Be careful when cooking with sugar, it’s extremely hot.
A spotlessly clean bowl is also important, as any slight grease residue will stop the egg whites from whipping up into stiff peaks.
TOP TIP: Measuring the sugar temperature is the key to successful Italian meringue buttercream. Use this Superfast Thermapen Thermometer for precise results, every time.
- Place the egg whites in a stand mixer with the whisk attachment.
- Place the caster sugar and water in a saucepan and heat gently. Using your Thermapen, continue heating until it reaches 117C (never walk away from hot sugar).
- Once the sugar mixture reaches about 110C, turn on the stand mixer and whisk the eggs to stiff peaks. Ideally, you want to reach stiff peaks at the same time the sugar reaches 117C.
- When ready, turn the whisk to the lowest setting and very carefully pour the sugar syrup into the mixer. Make sure not to let it pour over the whisk, as this could lead the hot styrup to splatter out of the bowl.
- Once added, turn the mixer up to medium and whisk until the mixture is completely cool. Again, this can take 10-15 minutes.
- Once cooled, reduce the whisk to the lowest setting again and add the softened butter in tablespoon-size pieces, ensuring each piece is fully mixed in before adding the next. You’re now ready to use your Italian meringue buttercream.