How To’sday: How to Make Swiss Meringue Buttercream

Swiss Meringue Buttercream

For the first several years of my training as a cake decorator, I used an icing composed primarily of Crisco and powdered sugar. And I’ve gotta admit, for someone decorating 1-2 practice cakes (and in later years, simply styrofoam cake forms) every month, there was nothing better: it’s snow white, doesn’t take long to bring to room temperature, holds it’s shape  and consistency even as it gets warm in the piping bag, and seemingly never spoils.

That icing served me well for a long time. But as I grew older I started to grow wary of the mysterious ingredients in Crisco, and the gritty texture of the powdered sugar irritated me more and more. I started to think perhaps it was time to up my game in the icing department. And it only took a teensy bit of digging around the cake-baking community to know that I needed to learn, above all other things, the art of Swiss Meringue Buttercream.

The very best buttercream
And boy am I glad I did. Each batch I make reaffirms my obsession with this icing: impossibly smooth and creamy, light and airy, shiny and stable, and delicately sweet. It freezes well, so it can be made in large batches even if you only have a small cake to bake. Because the sugar is dissolved, there is no grittiness whatsoever. It’s stable once applied, gives strength to your cakes, and is gorgeous enough to be used as an outer icing with no need for fondant. Plus, it can be adapted to just about any flavor you want.

I’ve now used this buttercream for two wedding cakes, a birthday cake, cookie icing, cupcake icing, and dinner party cakes. It’s extremely versatile and soooo tasty.

So today, I want to share it with you. And it’s not scary! Though it is a bit time-consuming, it’s pretty straight-forward to make. So let’s dive in and make some SMBC!

Items to wipe down with vinegar
The first step is to gather your equipment. A stand mixer (I’m sure you could do this with a hand mixer, but it would be a LOT more work), a whisk, a food scale, and a candy thermometer are the primary tools you’ll need that you may not already have. You’ll also need some measuring spoons and a small pot, but we’ll get to those in a minute.

Daub some white vinegar on a paper towel or napkin and wipe down the mixer bowl, the whisk attachment, the whisk, and the candy thermometer. You’ll be using them all to create the meringue, and meringue doesn’t create very well if any grease is on your equipment. Best to make sure, or you may not end up with a strong meringue for a base of your icing.

All the ingredients
Next, gather your ingredients. It’s a simple list: egg whites, granulated sugar, vanilla, salt, and of course, a lot of butter. A lot. Now as you can see, I use bottled egg whites (not to be confused with Egg Beaters). It turns out that one pint is the exact amount needed for a batch that perfectly fills my mixer bowl. I’ve heard some people say that bottled egg whites don’t create a strong enough meringue for SMBC, but I’ve been perfectly happy with the results of these. If you want to use fresh egg whites, you’ll need the whites of 15-16 eggs.

Weighing the sugar

To measure out the sugar, it’s significantly easier to measure by weight. If you don’t already have one, a food scale is a GREAT investment for your kitchen. You can zero out the scale with the mixer bowl already on top, and easily add your 750 grams.

Combine egg whites and sugar
Once the sugar is measured out, add the egg whites and candy thermometer to the mixing bowl. You can set them aside for now.

Next, it’s time to chop all that butter – all 10 sticks – into pieces. I generally go with pieces about a tablespoon in size. The butter should still be cold at this point. By the time you’ve made your meringue, it will be about room temperature when you add it to the icing. Make sure you don’t take your butter out of the fridge too early, or it will be too soft to make good icing. Once you’ve chopped up all the butter, set it near your mixer and turn back to the sugar and egg whites. It’s time to begin cooking!

Over a bain marie
Pour about an inch of water into the bottom of a small pot and place it on the stove. You don’t need much, in fact, you won’t want the bottom of the mixer bowl to touch the water. This is called a bain marie, which basically means a pot of simmering water. Set the mixer bowl onto the pot and turn on the stove to medium-high. Once the heat is on, whisk constantly until the mixture reaches 160°F.

Beat the egg whites and sugar until stiff

Once the mixture has reached 160°F, remove the candy thermometer and transfer the mixer bowl immediately to the mixer. Attach the whisk attachment and beat on medium (about a 4 on the Kitchen-Aid) for 2-3 minutes, then increase to high speed (all the way up!) You’ll whip the meringue for about 15-20 minutes until stiff peaks form and the sides of the bowl have cooled to slightly above body temperature.

Now what you have is a beautiful and delicious meringue! And this would be good to eat all on it’s own. But! We have quite a lot of butter to add, so onward and forward. Shake and scrape off any meringue that is on the whisk attachment and swap it out for the paddle attachment. Begin mixing at medium speed and start adding butter, one cube at a time, allowing each cube to be mixed in before adding the next. I usually wait about five seconds between each one.

Beginning to add butter
As you add butter, the meringue will begin to deflate and look thin. This is normal, just keep adding butter.

Butter is added but needs more mixing
Once you’ve added all the butter, don’t be discouraged if your icing doesn’t look, well, right. The photo above has all the butter added, but the mixture still looks rather disgusting. But now is the time for the true magic of SMBC to occur. Be patient and just keep whipping that icing, and you’ll watch it transform from something resembling curdled milk to shiny, creamy buttercream.

Still mixing
After a few more seconds, the icing will begin to look even worse. But be patient! It’s almost time!

NOW it's ready
Suddenly, magic! I urge you not to look away during the final seconds of whipping the icing, it really is fun to watch it come together.

Add vanilla and salt
Once the icing has reached this consistency, it’s time to add vanilla and salt, as well as additional flavors.

A word on vanilla: I love using real vanilla extract whenever possible. But as you can see, real vanilla extract will DEFINITELY affect the color of your icing. As it is butter-based, you’ll never have pure white icing when making SMBC, but using real vanilla extract will give an even stronger ivory tint. When I want a lighter, whiter icing, I use clear vanilla flavoring instead.

However you color or flavor your icing, there is really very little you can do to make this unappealing. Holy mother buttercream.

Icing complete!
Now beyond making the icing itself, here are a few extra tips I’ve learned about Swiss Meringue Buttercream:

Spreading/Base Frosting
SMBC can be spread with a knife or easily piped. For spreading, make sure you have more icing than you’ll actually want on the final cake. It’s always easier to smooth your icing by having the ability to scrape some off rather than trying to work with a minimal amount. Slather it on thick and then remove the extra as you smooth.

Though it’s not quite as easy as the Crisco-based icing I learned with, SMBC does pipe very well. The biggest tip I can offer is not to fill your piping bag very full. Because it is butter-based, the heat from your hands can melt the icing a little too much. I’ve found that this not only affects the texture, but the color. Start with small amounts in your piping bag, and it doesn’t hurt to make sure your hands aren’t too hot!

I love using this icing the same day I make it, but it can also definitely be stored. Store in an airtight container in the fridge for up to three weeks, or up to three months in the freezer. When you’re ready to use your stored icing, make sure you allow plenty of time for it to come to room temperature before you use it. If you’ve frozen your icing, let it thaw in the fridge overnight and then remove it from the fridge 3-4 hours before you want to actually use it. Even at room temperature, you may need to re-whip the icing with the paddle attachment for a few minutes.

SMBC Magic

Swiss Meringue Buttercream
Adapted from Sweetapolita

Makes about 15 cups, enough to ice and fill two 8-inch, three-layer cakes

750 g sugar, about 4 cups
1 pint/450 g liquid egg whites, about 15-16 egg whites
10 sticks  (2.5 pounds) unsalted butter
2 T vanilla extract
1/4 tsp salt

Lightly wipe the bowl of a stand mixer, a whisk, and the mixer whisk attachment with white vinegar to remove all traces of grease. Measure sugar into the mixer bowl using a food scale. Add the egg whites to the sugar and position the candy thermometer into the mixer bowl. Set aside. Cut butter into cubes about one tablespoon in size and set near the standing mixer so that the butter can come to room temperature while you prepare the meringue.

Add about an inch of water to a small pot. Place the mixer bowl onto the pot and place the pot on the stove over medium-high heat. Whisk the mixture constantly until it reaches 160°F. Remove the candy thermometer and place the mixer bowl on the standing mixer. Use the whisk attachment and whip until mixture is thick, glossy, and the outside of the bowl is only slightly warmer than body temperature, about 15-20 minutes. Switch over to the paddle attachment and turn to medium speed. Add butter one cube at a time about five seconds apart, allowing each to mix in.

Once all the butter is incorporated, increase speed to medium-high and whip until the icing is a silky, smooth texture. It will look curdled along the way, but keep whipping! Once it has reached that silky texture, add vanilla and salt and mix well.

If desired, add a few drops of icing color to tint the icing.

Flavor Variations
Here are a few variations on flavor that I’ve tried. There are, of course, countless others.

Espresso Buttercream: For every 5 cups of buttercream, combine 2 tablespoons of hot water and 1 1/2 tablespoons of instant espresso in a small bowl. Add to buttercream and whip until thoroughly combined.

Raspberry Buttercream: For every 5 cups of buttercream, add 1 c fresh raspberries and mix until desired coloring is achieved.

Blackberry Buttercream: For every 5 cups of buttercream, add 2 c fresh blackberry puree and mix well.

Almond Buttercream: Substitute 1 T almond extract for one of the tablespoons of vanilla extract in the last step.