Italian Meringue Buttercream is silky, buttery but still light. This buttercream can be used as a filling and topping for cakes and cupcakes. This buttercream is easy to spread or pipe and holds its shape perfectly plus is more stable in warm conditions than regular buttercream. Master this recipe to complement all your delicious cakes and cupcakes. This recipe is enough to fill and cover a 3 layer 23cm/9in cake.
Place the 1 cup castor sugar and water in a pan. Pop in a candy thermometre and partially cover with the lid. The lid is ajar and will catch the steam as it rises, The steam dissolves the sugar caught around the edge of the saucepan.
Place over low to medium heat until the sugar is dissolved and the syrup reaches 245°F/120°C.
At the same time as the sugar syrup is cooking start the meringue. Beat the egg whites in a stand mixer with the whisk attachment until soft peaks form – about 2 minutes. Don't overbeat.
While still whisking, sprinkle in the 1/4 cup sugar and fine salt. Beat well on high speed.
By this time the syrup should be ready.
Pour the sugar syrup into the meringue, whisking on high speed. in a slow and steady stream. Aim to pour the syrup between the whisk and the side of the bowl right onto the meringue. It should take about 1 minute to pour all the syrup in.
After 2 minutes reduce the speed to medium and continue to beat until the mixture cools. Depending on the temperature of your kitchen this will take anywhere from 5 to 15 minutes or longer. See my notes for extra tips.
Once cool and not before, slowly add the butter tablespoonful by tablespoonful. The mixture will deflate slightly but all is well.
If your butter melts the meringue is still too hot. Beat until it cools. If necessary, remove the bowl and place it in the refrigerator for a while. Then start again. Check the recipe notes.
Increase the speed to high and beat for 2 or 3 minutes until light and fluffy.
Use immediately or store in the refrigerator for a week or the freezer for 2 months.
Tips for success.
Grease is the enemy of meringue - clean the bowl and whisk thoroughly before beating egg whites.
Partially cover saucepan when boiling sugar syrup - this ensures captured steam dissolves the sugar caught on the sides of the saucepan.
Bring the syrup up to the correct temperature - 245°F/120°C
Don't over beat egg whites before adding sugar. Once egg white collapse and become liquid again they can't be rescued.
Pour the hot syrup between the sides of the bowl and the beater directly into the meringue.
Let the meringue cool before adding the butter. Check how cool the meringue is by stopping the mixer and testing with your finger. Often the bowl is still warm but the meringue has cooled
Have the butter at room temperature but not melted or greasy. Butter must still be firm.
What can go wrong and how to fix it.There are a couple of things that can go wrong when making this recipe that you need to be aware of.
Once hot syrup is added, meringue must be beaten at continuously until cool. If your kitchen is hot, place ice in a clean towel and wrap around the bowl to cool the meringue.
If the mixture becomes soupy after adding the butter, the meringue may have still been a bit too warm. Stop adding butter. Cool the mixer bowl using ice as per step 1.
If the mixture remains soupy, place bowl and whisk into refrigerator until cool and whisk again until the buttercream comes together.
Butter must be a cool room temperature. If you find lumps of butter it means that the butter is too cold. Stop adding the butter. Bring the butter to room temperature. Also try holding a warm towel against the sides of the bowl until the butter softens and incorporates.
Italian Meringue Buttercream usually can be fixed by beating, beating and more beating. This is an emulsion. As long has the temperature is correct - not too warm and not too cold - it will work. Don't panic when you see the meringue collapse and separate as you add the butter because it will soon come back together again.Flavouring buttercream Try adding one of the following
3 teaspoons vanilla extract
beans of one scraped vanilla pod
1/2 cup melted, cooled chocolate
2 tablespoons instant coffee granules dissolves in 2 tablespoons of water
1/4 cup fruit puree such as raspberry or strawberry