If you love the silkiness of Swiss Meringue Buttercream and the rich lemon flavour you find in homemade lemon curd, trying this Lemon Swiss Meringue Buttercream is a must. You only need these two recipes together to create a unique frosting that is easy to pipe into beautiful designs or to use as a filling when layering cakes, to cover cakes, and even use as a complimentary cream for various desserts. It is so versatile, its use is only limited to ones imagination.
This Lemon Swiss Meringue Buttercream recipe involves combining two recipes in specific quantities to achieve a silky, easy to pipe frosting that is rich in lemon flavour and retains the delicate and exquisite qualities of a Swiss Meringue Buttercream. You will first need to make my very easy and quick lemon curd which you will refrigerate and cool before adding to the Swiss Meringue Buttercream. The next step will involve making my most sought after Swiss Meringue Buttercream recipe. You will combine the two at the end and you will have the tastiest, creamiest Lemon Swiss meringue Buttercream you have ever tried. You will also be able to watch my full complete step by step recipe video as a companion guide to achieve this incredible recipe.
Watch my how to make a Lemon Swiss Meringue Buttercream recipe video below.
Lemon Swiss Meringue Buttercream
Lemon Swiss Meringue Buttercream Cupcake.
Author: Katherine Walton
For the Lemon Curd
-110 grams (1 metric cup) of caster sugar
-40 grains (1/4 metric cup) cornflour
-125 ml (1/2 metric cup) of tap water
-65 ml (1/4 metric cup) freshly squeezed lemon juice
-1 teaspoon lemon rind
-30 grams unsalted butter at room temperature
-1 egg yolk lightly whisked at room temperature
For the Swiss Meringue Buttercream
-185 grams of fresh egg whites at room temperature (egg whites of 4 Jumbo eggs)
-370 grams of caster sugar (1 2/3 Metric cups)
-370 grams of unsalted butter at room temperature
-2 teaspoons of clear vanilla extract or any other flavour
-Digital food thermometer
Firstly, make the Lemon Curd.
- Add caster sugar, cornflour, water and lemon juice to small pan. Stir ingredients with a metal spoon until all well combined.
- Cook over medium heat, stirring with a metal spoon constantly. Do not let mixture stick to the bottom of the pan or burn.
- Mixture will begin to thicken up after a few minutes.
- Continue to stir until mixture thickens and becomes smooth.
- Add the butter and whisked egg yolk and cook for three minutes until all well combined.
- Do not let the curd stick to the pan or burn. Continue to stir through.
- Add the lemon rind and stir through until smooth and well combined.
- Set aside and refrigerate immediately. The lemon curd will harden in the fridge, therefore will need to bring to room temperature to soften it and be able to mix it with the Swiss Meringue Buttercream at the final stage of this recipe.
Secondly, make the Swiss Meringue Buttercream.
- Fill a medium sized saucepan with about 2 centimeters of water. Bring to a boil then reduce to medium heat.
- Place egg whites and caster sugar in a clean heat proof stand mixer bowl. Make sure bowl is completely free of grease. If in doubt wipe with white vinegar or lemon juice. Whisk together until all incorporated, then place bowl on top of sauce pan. Make sure the bowl does not touch the water.
- Whisk and mix ingredients until sugar dissolves completely. Scrape the bowl on the sides with a silicone spatula so that all the sugar dissolves with the egg whites.
- Temperature should reach 70 degrees Celsius (158 Fahrenheit). If you do not have a food thermometer you can rub the mixture between your fingers and you should not feel any sugar granules. The mixture will also change and become runny and foamy. (You can watch how it changes on my Step by Step video above).
- Transfer bowl to stand mixer and mix at medium-high speed until the meringue starts to come together. It should become thick and glossy and increase in volume. The meringue should not be runny or fall from an upside down spoon.
- Transfer meringue into another large bowl. Set aside until it has completely cooled to room temperature.
- Wash mixer bowl and add unsalted butter and mix at high speed until butter changes colour to a very pale cream and it increases in volume. It can take up to 10 minutes or more. You must scrape the sides off the bowl to ensure all butter is beaten.
- Once butter reaches a very pale consistency, mix in the meringue and mix together from medium to highest speed for 5 minutes.
- Scrape the bowl and set aside.
Third, and last step is to combine the completely cooled Lemon curd and Swiss Meringue Buttercream.
- Once the Swiss Meringue Buttercream is complete and the Lemon Curd has completely cooled down to room temperature. You will add the lemon curd into the mixer bowl that has the finished Swiss Meringue Buttercream.
- Combine and mix both the Lemon Curd and Swiss Meringue Buttercream in the mixer bowl.
- Scrape the bowl once or as necessary to ensure both are well combined.
- At this stage you may choose to add food colouring of your choice. I have opted to add yellow gel food colouring as shown in the how to video above. You may also leave the frosting in its natural pale ivory colour.
How to make sure this recipe is successful?
The most important step in this recipe is to ensure the lemon curd completely cools to room temperature before adding it to the Swiss Meringue Buttercream. If the lemon curd is still warm, the frosting will curdle and separate and you will have to start the recipe from scratch. At the same time you must make sure that the meringue has cooled to room temperature as well before adding it to the beaten butter when making the Swiss Meringue Buttercream stage.
How much frosting does this recipe make?
This recipe yields 5 metric cups of frosting. Depending on the piping tip used and style, this amount is for 12 to 24 standard cupcakes. This frosting is also enough to layer an 8″ by 6″ round cake including a crumb coat.
How are the ingredients measured in this recipe?
In this recipe and in all of my recipes I provide all ingredients in grams and in mL where applicable. I also provide the ingredient quantities in METRIC cup measurements. However, be aware that cup measurements and spoon measurements vary in different countries. Therefore, I highly recommended the use of scales where applicable to measure ingredients to achieve exactly what the recipe intends.
How to separate egg whites from egg yolks?
It is best to separate the egg whites from the egg yolk when the eggs are cold. Then leave the egg whites in a bowl covered to bring to room temperature.
What is caster sugar and can I substitute it in this recipe?
Caster Sugar is also known as super fine granulated sugar. Not to be confused or replaced with icing sugar also known as powdered sugar. You may replace the caster sugar with standard granulated white sugar in this recipe as in both the lemon curd and the Swiss meringue buttercream, the sugar is dissolved in liquid.
How to store and what is the shelf life of this Lemon Swiss Meringue Buttercream?
This Lemon Swiss Meringue Buttercream frosting can be kept refrigerated for up to 5 days. Bring to room temperature before use. You may simply re whip with a metal spoon. In rare cases the frosting may seem like it has separated during its storage time. You can easily fix it by re whipping the whole batch back in the mixer. Mix until the frosting comes together again.
Do you need to use a food thermometer?
I recommend the use of a digital food thermometer in order to know if the temperature of the egg whites has reached 70 degrees Celsius (158 Fahrenheit) to destroy bacteria which can be found in raw eggs.