Italian Buttercream Wedding Cake: A Step-By-Step Guide

Italian buttercream is a popular choice for wedding cakes due to its silky texture and ability to be flavoured and coloured in endless ways. It is made by whipping egg whites with sugar syrup and softened butter. This guide will take you through the process of making Italian buttercream, from preparing the ingredients to storing the final product.

The ingredients you need

To make Italian buttercream for a wedding cake, you will need the following ingredients:

• Eggs — Fresh eggs are recommended over carton egg whites, as they whip up better and are vital to a stable buttercream frosting. You will need both the egg whites and the yolks, so separate them carefully, making sure that no yolk gets into the whites.
• Sugar — Use regular granulated sugar for the sugar syrup. It needs to reach a temperature of 240ºF–250ºF to ensure that the sugar is stable enough to be whipped into the frosting.
• Butter — Use unsalted butter at room temperature. This will ensure that you don't end up with lumps of butter that you can't whip out.
• Cream of tartar — This helps stiffen the egg whites and gives them more volume as they whip up. If you don't have any, you can substitute an equal amount of white vinegar or lemon juice, or omit it if you're using the sugar syrup to stabilise the buttercream.
• Salt — Just a little salt will bring out the flavour of the Italian meringue buttercream.
• Flavouring — You can use vanilla, orange blossom water, rose water, fruit reductions, other extracts, or chocolate (melted and cooled).
• Food colouring — If you want to add colour to your Italian buttercream, use gel or paste colours, not liquid ones, as these will cause the frosting to break.

For a two-layer, 9-inch cake, you will need the following quantities:

• 3 ounces of water
• 12 ounces (1 cup plus 1/3 cup plus 1 tablespoon) of granulated sugar
• 6 ounces of egg whites (about 3 egg whites)
• 1 pound (4 sticks) of unsalted butter, softened at room temperature, and cut into pieces
• 1 teaspoon of vanilla extract

However, if you desire a more extravagant amount of buttercream, as in the source recipe's four-tiered wedding cake, use the following quantities:

• 1/2 cup of water
• 1 pound (2 1/4 cups) of granulated sugar
• 8 ounces of egg whites (about 4 egg whites)
• 1 1/2 pounds (6 sticks) of unsalted butter
• 1 1/2 teaspoons of vanilla extract

How to make the syrup

To make the syrup for Italian buttercream, you'll need to combine sugar and water in a small, non-stick saucepan. Bring this mixture to a boil over medium heat, stirring occasionally until the sugar dissolves. Do not stir once it reaches a boil. You'll know the syrup is ready when it reaches a temperature of between 240°F and 250°F.

It's important to monitor the temperature of your sugar syrup closely. You can use a candy thermometer to do this. If the syrup gets too hot, it could affect the consistency of your buttercream.

Once your syrup reaches the right temperature, remove it from the heat. While it's still hot, you'll need to slowly drizzle it into your egg whites as they whip in your stand mixer. This will create a stable and silky-smooth meringue base for your Italian buttercream.

How to make the meringue

To make the meringue for Italian buttercream, you'll need to separate the egg whites from the egg yolks. You can do this by cracking the egg over a bowl, being careful not to pierce the yolk, and then letting the white strain through your fingers into the bowl. Alternatively, you can crack the egg and gently move the yolk back and forth between the two shell halves, allowing the white to drip into the bowl. It's important to ensure that none of the yolk gets into the whites.

Next, place the egg whites into the bowl of a stand mixer with the whisk attachment. Add a pinch of salt and, if desired, 1/4 teaspoon of cream of tartar, which will help the egg whites to stiffen and give them more volume. Start beating the mixture on high speed until soft peaks form.

While the eggs are whipping, make a sugar syrup by combining sugar and water in a medium-sized saucepan. Stir to distribute the water evenly, then cover with a lid and bring to a boil. Keep the lid on for around 5 minutes to ensure that all the sugar granules are dissolved. If they're not, your sugar may crystallise and become grainy.

Remove the lid and continue boiling the mixture without stirring until it reaches 240-250°F. This is important to ensure that the sugar is stable enough to be whipped into the meringue. When the syrup reaches this temperature, slowly drizzle it into the egg whites with the mixer running on low speed. Try to pour the syrup between the whisk attachment and the side of the bowl to prevent splattering.

Once all the syrup has been added, increase the mixer speed to high and beat until the mixture forms stiff peaks. You can speed up the cooling process by placing ice packs at the base of your mixer or placing the meringue in the fridge for 15 minutes.

Once the meringue is cool, you can start adding the butter. It's normal for the meringue to deflate and look curdled at this stage, but don't worry—just keep adding the butter and whipping the mixture. You can also add vanilla or other flavourings at this point. Keep mixing until the Italian buttercream becomes light and fluffy, and you're done!

Combining the syrup and meringue

Firstly, ensure your sugar syrup has reached the optimal temperature. It should be at least 240°F, but it can go as high as 248°F to 250°F. This temperature range ensures the sugar is stable enough to be incorporated into the meringue.

While the syrup is heating, prepare your meringue. In the bowl of a stand mixer, combine the meringue powder, water, and a pinch of salt. Start beating at high speed. You'll know it's ready when the mixture first looks foamy, then turns white, and you begin to see tracks in the bowl. At this point, slowly add in the remaining sugar with the mixer running. Increase the speed to high and beat until the meringue is stiff.

Now, the critical part: combining the syrup and meringue. When your syrup reaches the desired temperature range, remove it from the heat. With the mixer running at low speed, carefully pour the hot syrup down the side of the mixing bowl, avoiding the whisk or beaters to prevent sugar threads from forming. Once all the syrup is in, continue mixing until the meringue cools to around 80°F. You can speed up this process by wrapping an ice pack around the mixing bowl.

This step requires precision and attention to detail. Adding the syrup too quickly or pouring it onto the whisk/beaters can result in a messy, unsuccessful attempt. Take your time and work carefully.

Once your meringue has cooled, you can move on to the next step of adding the butter, which will transform your mixture into a silky, smooth Italian buttercream.

Adding the butter, flavouring and colouring

Add the butter a few pieces at a time, with the mixer running at medium to medium-high speed. You can use unsalted butter, but it is important that it is at room temperature. The meringue will deflate a bit, and may begin to look curdled. This is normal, so don't panic! Just keep the mixer running and adding the butter.

Soon, the Italian buttercream will begin to come together around the whisk, then in the rest of the bowl. Once most of the butter is in, add your choice of flavouring. Vanilla extract is a popular choice, but you can also use vanilla beans, emulsions, ground-up freeze-dried fruit, rose water, orange blossom water, fruit reductions, or other extracts.

This is also the time to add food colouring, if you want to. Be sure to use gel or paste colours, not liquid ones, as these will cause the frosting to break.

Frequently asked questions