Bittersweet Chocolate Swiss Meringue Buttercream

Bittersweet Chocolate Swiss Meringue Buttercream
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yellow cake with bittersweet swiss meringue
A perfect frosting!

If you grew up in the United States, you’ve had what’s called American buttercream frosting. You know the stuff; basically, powdered sugar and butter beaten together, with a bit of flavoring and coloring added. We refer to that as lard frosting, because the texture’s reminiscent of lard: heavy and greasy. For years, that was one of our main objections to cake. It had frosting on it, American buttercream frosting, and we just can’t deal with it.

Now that we’re more knowledgeable, we know of Swiss meringue buttercream frosting. It’s exactly what a frosting should be, super smooth, light, not too sweet, and not the least bit greasy or heavy. But, is it difficult to make? Not really. Follow along as we scratch up a batch, and see for yourself.

We’ve made Swiss meringue buttercream for several cakes that we’ve posted, but, this time, since we’re learning more and more about making SWB, we thought we’d have a separate post that includes some of the ways SWB can fail, and how to fix them (we had ours fail for this post), but, thanks to this post, we knew what to do.

Finally, this recipe is based on one from baking a moment, but we cut back on the sugar (the original was too sweet for us, hiding the chocolate flavor) and increased the size to cover a three-layer cake.

Bittersweet Chocolate Swiss Meringue Buttercream

Yield: Enough for a three-layer 8-inch cake

Bittersweet Chocolate Swiss Meringue Buttercream


  • 4 egg whites
  • 175 g (1 cup - 2 Tbs) sugar
  • 1/2 tsp vanilla extract
  • 160 g (5 1/3 ounces) bittersweet chocolate
  • Pinch cinnamon
  • 300 g (2 2/3 sticks) unsalted butter, room temperature

Abbreviated Instructions

Construct a double boiler by fitting the bowl of a stand mixer into a saucepan with about an inch of water. The bowl should not touch the water.

In the bowl, whisk together egg whites and sugar and bring the water to a simmer. Continue whisking until sugar is completely dissolved and mixture is quite hot (160°F).

Place bowl on stand mixer fitted with the whisk attachment, add vanilla, and whip on high until completely cool, about 10 minutes.

Meanwhile, melt chocolate in a heatproof bowl, either by setting over simmering water or by microwaving in 20-second increments and stirring in between. Add cinnamon and stir in. Let cool.

Once the egg white mixture is cool, decrease the speed of the mixer to low, and add the butter in 1-2 tablespoon increments, waiting until the butter is incorporated before adding the next. Continue until the frosting looks light and fluffy.

With the mixer still on low, add the chocolate and mix until uniform, scraping the bottom of the bowl to ensure everything is mixed.


If the frosting doesn't thicken properly, place bowl in the refrigerator for 20 to 30 minutes, then re-whip.

Ingredient discussion:

We use eggs from happy, foraging hens. The better the hens are treated, the better the eggs. Simple. For the chocolate, we use the best we can, which in this case is Callabaut 72% cacao dark chocolate. To buy it at a reasonable price, we get the 5 kilo bars (11 pounds). The pinch of cinnamon is there to help bring out the chocolate flavor. Another good choice would be to add a bit of coffee, perhaps a tablespoon or so, but don’t add it directly to the chocolate; instead, add it to the frosting at the end. And, of course, only 100% real vanilla.

Procedure in detail:

double boiler
A simple, improvised double boiler: a pan and the mixer bowl.

Assemble double boiler. Find a pan that the bowl of your stand mixer will fit in without touching the bottom. Add about an inch of water (don’t let the mixer bowl touch the water) to the pan and place over high heat. Once it boils, lower to a simmer.

making Swiss meringue
All the sugar should dissolve and the mixture should look like a white syrup.

Heat egg whites and sugar. Add the egg whites and sugar to the mixer bowl, place over the simmering water, and start whisking. Continue whisking until the sugar dissolves completely and the mixture resembles a white syrup. If you have a thermometer, the temperature of the syrup should be between 160-165°F. You don’t need to whisk the mixture vigorously, just enough to keep it moving.

adding vanilla
You can add the vanilla at pretty much any time in the process.

Add vanilla and whip. Now you’ll see why this requires a stand mixer. Place the bowl on the stand mixer fitted with the whisk attachment, add the vanilla, and whip on high. It’ll fluff up rapidly, but keep on whipping until it cools completely. This can take over 10 minutes! Imagine if you had to whip this by hand. Whew. Test the temperature periodically by placing the back of your hand on the bowl. When cool, decrease the mixer speed to low.

Melt chocolate. While the mixer is whipping away, you might as well melt the chocolate. We did this by placing it in the microwave and heating for 20 seconds, stirring, letting it sit for about 30 seconds, and repeating until the chocolate was smooth (we’d learned from the first batch; we had a few little pieces of unmelted chocolate, making for frosting with tiny hard chocolate bits).

Add cinnamon. Add the pinch of cinnamon to the chocolate and stir it in. Let the chocolate sit while the meringue finishes cooling.

chunk of butter
The exact amount of each chunk of butter doesn’t matter; we just cut off pieces and drop them into the cooled meringue.
Swiss meringue buttercream
Even if the meringue collapses, don’t worry; continue on through the end of the recipe. It might come back. If not, you can fix it.
fluffy Swiss meringue buttercream
The first batch we had to chill for a bit to come back, but, the second came back by itself.

Add butter. Back to the mixer. With the mixer on low, start adding the butter in 1 to 2 tablespoon-sized chunks, waiting until the each piece is incorporated before adding the next. If the mixture starts to look curdled, don’t panic; just let the mixer keep on working until it comes back together. It will. If the mixture looks runny, don’t panic; just continue on — it might come back, but, if not, read the note below to fix it.

adding chocolate
The original recipe said to fold in the chocolate and we did. It wasn’t worth the trouble; next time, we just let the mixer do the work. It came out perfect.

Add chocolate. With the mixer still on low, slowly pour in the chocolate and mix in completely. You’ll have to stop the mixer and scrape the bottom of the bowl once in a while, to ensure that all the buttercream gets mixed in with the chocolate.

frosting a cake
Apply a crumb coat to seal in the crumbs, then freeze for 15 minutes, and apply the final, smooth, beautiful, coat.

Frost. Now you’re ready to frost your cake with the best frosting ever.

Note: If your frosting doesn’t whip up — this seems to happen if everything is too warm — and looks like a thick syrup, don’t panic; just continue until you add the flavorings (it sometimes comes back just like magic, especially if some of the butter is slightly cool). If it’s still a thick syrup, place it in the fridge for 20 to 30 minutes, then start whipping and it’ll turn out perfectly.

This is frosting. Just about the only kind we like, super-smooth and creamy, light as air, and not too sweet, this stuff makes a cake taste good. As we said above, American buttercream makes us want to avoid cake. It’s more trouble, but, once you make frosting like this, you’ll never go back. Five smooth chocolicious stars!

Worth the trouble?

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