When I discovered Swiss Meringue buttercream (or SMB) several years ago, I was intimidated by it. I couldn’t just throw everything in a mixing bowl and start mixing as I had done with the American-style buttercream I had been previously making. SMB required a bit of extra time and a process. But let me tell you, it is so worth it. SMB is luxuriously light, creamy and delicious. It’s silky, fluffy and smooth texture makes it a DREAM for filling and icing stacked cakes. It’s stable and holds its shape when piped. People ask me often how I get such sharp edges and a beautiful finish under my fondant. Well, this buttercream is it.
You begin the process of making SMB by heating egg whites and granulated sugar over a pot of simmering water. This process is to cook the egg whites and melt the sugar all while whisking continuously to avoid any scrambling. Once the egg white mixture reaches 160F, it is strained through a sieve into a mixing bowl of a stand mixer and using the whisk attachment, beaten until stiff peaks form and the bowl is room temperature. At this point, softened butter is popped in piece by piece and then, you leave it be and walk away. What?! Leave it be? Yep.
This is the time in SMB making that most people think they’ve destroyed it and they pitch all of that glorious (albeit, ugly at this point) buttercream. It’s quite possible your buttercream will look curdled, or super deflated. It might even look separated. But it’s ok. Let it keep mixing. This can take up to several minutes. Keep mixing and it will come together into creamy, silky and smooth buttercream.
Once the buttercream has come together, it is time to add flavorings and a pinch of salt. SMB is a blank canvas suitable for many, many types of flavorings. Jams, curds, cookie butters, nut butters, extracts, chocolates, etc. Add it options are endless so don’t be afraid to experiment.
One of the concerns people have before making SMB or any meringue style buttercream is that it will be too buttery. In comparison to American style buttercreams that are mostly sugar and the sugar taste is in the forefront, SMB is mostly butter with the addition of a sweetened meringue. SMB is meant to hold a large amount of flavor. It is a creamy, silky blank canvas. So don't skimp on the flavorings. I always suggest to SMB beginners who ask me about the buttery flavor, to try a fruit or chocolate flavored buttercream first so you can really get a sense of how delicious, adaptable and amazing this buttercream truly is.
Some notes and tips:
*Mixing bowl and utensils must be grease free otherwise the eggs won’t whip up properly. They’re temperamental like that. Wipe down your bowl and utensils with a clean cloth and lemon juice or vinegar to remove remaining fat residue.
*Make sure your butter is room temperature. If your butter is too cold, the buttercream will have lots of air holes and not be as smooth as it can be.
*Bring the temperature of your egg/sugar mixture up slowly. Rushing this process will result in scrambled egg whites.
*Use a candy thermometer to make sure your temperature reaches 160F.
*If you’re finished buttercream appears soupy, it’s possible that the butter was too warm, pop the bowl into the refrigerator for 10-15 then mix again.
*To help avoid air pockets in your buttercream, once the butter is mixed in, mix on low speed. You do not want to incorporate air. Mixing on low does take longer but it’s worth it in the end to not have blowouts or air bubbles in your buttercream and under your fondant finish.
*You can add quite a bit of liquid into your buttercream. When adding liquids, such as fruit purees and other liquids, mix in a little at a time. The liquid needs to be able to fully emulsify into the buttercream.
*If your buttercream has been frozen or in the refrigerator, it must come up to room temperature to be remixed properly. Cold buttercream will separate. If you start mixing your buttercream and find that it is still too cold and is separating, you can help bring the separated mixture back together by using a kitchen torch to warm the buttercream. While the mixer is on, run the kitchen torch flame along the outside bottom, of the metal mixing bowl, back and forth, until the buttercream starts to come together.
Vanilla Bean Swiss Meringue Buttercream
Yield: Approx. 10 cups
10 (300g) large egg whites, fresh
2 ½ cups (500g) granulated sugar
3 ½ cups (793g) unsalted butter, room temperature, cut into cubes – I use European style butter
1/8 tsp of fine sea salt
1 tbsp Pure Vanilla Extract (I use Nielson Massy)
2 tbsp Pure Vanilla Bean Paste (I use Nielson Massy)
Using a kitchen scale, weigh out the egg whites and granulated sugar together in a non-reactive bowl. Clip a candy thermometer onto the side of the bowl and place over a pot of simmering (not boiling) water, whisking constantly and gently until temperature reaches 160F. Using a sieve, strain the egg white sugar mixture into the bowl of a stand mixer. Mix on medium speed with the whisk attachment until the mixture is glossy, reaches stiff peaks (but not dry) and the mixture and bowl are no longer warm. You cannot add butter if the mixture or bowl is warm or the butter will just melt when added. Once the mixture reaches stiff, glossy peaks, you have Swiss Meringue (Yay!) but we’re going for buttercream here, so onward. Switch out the whisk attachment for the paddle attachment and mix on low speed. Add the butter cubes, a couple at a time, until incorporated. Now, just let it mix. It might curdle or look lumpy but that’s ok. Keep mixing. This could take a few minutes. The buttercream is ready when it is smooth, satiny and creamy. Keep mixing on low and add the salt and flavorings.
*This recipe can be halved.
*The buttercream can be stored at room temperature for two days, in the refrigerator for tightly sealed for two weeks or in the freezer for 2 months.
Variations: There are endless options of add ins for Swiss Meringue buttercream. You'll notice that most of the variations listed below say "to taste". Always try a little bit at a time and keep adding until you're satisfied with the flavor.
Chocolate: Omit vanilla bean paste. Add 3 cups (600g) of melted and cooled high quality bittersweet chocolate. You can also use milk or white chocolate as well.
Fruit Purees or Reductions: Add fruit puree or reduction to taste, about 1 cup
Brown Sugar: Replace the granulated sugar with brown sugar
Nut and Cookie Butters: Add 1 cup or more (to taste)
Caramel: Add ¾ cup to 1 cup cooled caramel or dulce de leche (to taste)