Dark Mocha Cake with Caramel Swiss Meringue Buttercream and Salted Milk Chocolate Buttercream

Here's to dairy-producing animals everywhere!

Here’s to dairy-producing animals everywhere!

This post is dedicated to my gorgeous Husband, my sweet Beast Cat, and my other darling Beasties.

🙂 Kitchenchanted is one year old! 🙂

I began my blogging adventure one year ago today. It’s amazing, and a little scary, just how quickly that year has gone by. To celebrate my Bloggiversary (hee!), I made this wondrous creature with the equally wondrous name: Dark Mocha Cake with Caramel Swiss Meringue Buttercream and Salted Milk Chocolate Buttercream. Whew!

I miss Ireland.

I miss Ireland.

This cake is just the showstopper to celebrate my first year of blogging. I took the fudgy chocolate cake layers from this peanut butter and chocolate cake, and added twice the amount of espresso to rev up the mocha flavor. See, in the peanut butter version, the cake has a deep, dark chocolate flavour, and you can’t taste the coffee. For this cake, I wanted something darker to complement the sweet caramel Swiss meringue buttercream and the salted milk chocolate buttercream. The mocha flavour comes through loud and clear here, just as I wanted!

Don't close your eyes. It'll sneak up and nip you!

Don’t close your eyes. It’ll sneak up and nip you!

Next, I made caramel, because the Swiss meringue buttercream recipe I was using fussily demanded that I add homemade caramel to it. Sometimes caramel can be very cranky, and it was so this time. I had to throw away my first attempt, but the second attempt was a charm. The finished caramel Swiss meringue buttercream is subtly sweet, with a delicate caramel flavour. The texture is silky and thick, just as a Swiss meringue buttercream should be. It contrasts gorgeously with the dense, fudgy mocha cake layers.

I feel sudden lust for Captain Kirk.

I feel sudden lust for Captain Kirk.

I needed something extravagant for icing the outside of the cake, and I didn’t like the dark chocolate icing that was posted along with the Swiss meringue buttercream recipe. So I turned to Scratchville (my corny euphemism for one’s own creativity), and came up with a milk chocolate buttercream which derives its flavour from melted milk chocolate beaten into an American buttercream. To decrease the sweetness and add some complexity (not to mention jump onto the sweet / salty bandwagon), I eschewed unsalted butter for salted. And it worked perfectly! The salted milk chocolate buttercream is sweet but a little bit salty, very, very chocolate-y, and the only accompaniment I would want for this cake. I’m so glad I went with my instincts and made my own icing. It is mind-blowingly good, so much so that I looked at it in wonder – “Did I do that?”

Yep. I did. 🙂

This cake slice would like to dedicate its life to gustatorial greatness.

This cake slice would like to dedicate its life to gustatorial greatness.

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Dark Mocha Cake with Caramel Swiss Meringue Buttercream and Salted Milk Chocolate Buttercream

Yield: One 8″, three-layered cake


For the cake:
1¾ cups plus 2 TBS all-purpose flour
1¼ tsp baking soda
¾ tsp salt
1½ cups unsweetened cocoa powder, plus more for dusting pans (unless spraying pans with nonstick spray such as Baker’s Joy)
1 cup boiling water + ½ cup espresso or strong coffee; OR 3 TBS instant espresso or coffee powder + 1½ cups boiling water
¾ cup sour cream
1 TBS vanilla extract
3 sticks unsalted butter, at room temperature
2½ cups plus 2 TBS sugar
3 large eggs, at room temperature

For the caramel:
3/4 cup sugar
1/4 cup water
1/4 cup heavy cream

For the Swiss meringue buttercream icing:
4 egg whites
1/2 cup sugar
3 sticks unsalted butter, at room temperature and cut into 1 TBS pieces
the finished caramel (see above)

For the milk chocolate buttercream icing:
3 sticks salted butter, at room temperature**
4 cups powdered sugar
2 TBS cocoa powder
2 – 6 TBS heavy cream (start with 2 TBS & add more cream, 1 TBS at a time, to achieve a thinner consistency, if desired)
8 oz. milk chocolate (NOT chips!***), melted and still just barely warm****


For the cake:
Preheat oven to 350˚F. Spray 3 8″ round cake pans* with Baker’s Joy or similar and line the bottoms of the pans with parchment paper; spray the parchment paper. Alternatively, butter the insides of the pans and dust with cocoa powder, shaking out the excess, and line the pans with parchment paper. Note: I highly recommend lining the pans with parchment paper, as the cakes tend very much to resist coming out of the cake pans.

In a medium bowl, combine the flour, baking soda, and salt. Stir with a fork or whisk to blend and set aside.

Combine 1 cup water and 1/2 cup espresso. The mixture should measure 1 1/2 cups. Heat mixture to boiling in microwave. In a medium bowl, combine the cocoa powder and espresso mixture (or combine the cocoa powder, 1 1/2 cups boiling water, and 3 TBS instant espresso powder). Whisk until smooth; set aside to cool slightly. When cooled down a bit, whisk in the sour cream and vanilla until smooth. Set aside.

In the bowl of an electric mixer, beat the butter on medium-high speed until smooth, about 1 minute. Gradually blend in the sugar and whip on medium-high speed until light and fluffy, 2 – 3 minutes more. Blend in the eggs one at a time, scraping bowl after each addition.

With the mixer on low speed, add the dry ingredients and the sour cream mixture alternately, beginning and ending with the flour mixture and beating each addition just until incorporated.

Divide the batter evenly between the prepared pans.* Bake the cake layers for about 30 – 32 minutes or until a toothpick inserted in the center comes out clean, rotating the pans during halfway through to ensure even baking. Transfer the baked cake layers to a wire rack and let cool in the pans at least 10 minutes before inverting onto the rack to cool completely.

For the caramel:
Whisk together the sugar and water in a small, heavy-bottomed saucepan. Heat on medium without stirring at all; allow mixture to come to a boil, still without stirring at all. (Stirring after the mixture has reached a boil will cause large sugar crystals to form.) Let mixture boil until it reaches a deep golden colour; immediately remove from heat and whisk in the cream. When the cream is added, the mixture will bubble up and emit copious amounts of very, very hot steam, so do not lean your face into the mixture! Transfer the caramel to a smaller container, if you wish. Allow the caramel to cool; it should not be warm when added to the Swiss meringue buttercream.

If storing the caramel:
If not using the caramel the same day, it is likely to harden. This is normal. When you are ready to make the Swiss meringue buttercream, place the vessel containing the hardened caramel into a saucepan of simmering water; the caramel will soften after about 15 – 20 minutes. Set aside and allow to mostly cool; stir vigorously to incorporate both the hardening pieces and the soft parts of the caramel. Add the still slightly warm caramel, about 1/8 tsp at a time, to the Swiss meringue buttercream when the recipe indicates it is time to add the caramel. It is fine if this takes a long time, as you cannot overbeat Swiss meringue buttercream icing. (You probably could, but doing so would take hours.)

For the Swiss meringue buttercream icing:
Place egg whites and sugar in a heatproof bowl over a saucepan of simmering water. Heat, whisking constantly, until the sugar is completely dissolved and the mixture reaches 160˚F (about 5 – 7 minutes). Transfer mixture to the bowl of an electric mixer (I always just cook the egg whites and sugar in the bowl of my electric mixer) and beat on medium-high speed with the whisk attachment until the mixture forms stiff peaks and the bowl is cool to the touch, about 7 – 9 minutes. Reduce speed to medium and add the butter, 2 – 3 TBS at a time, beating until each addition is thoroughly incorporated before adding the next 2 – 3 TBS of butter. Fear not if the mixture appears soupy, curdled, or separated; this happens frequently when making Swiss meringue buttercream. Simply increase speed to high and continue to whip until the mixture smooths out. Don’t worry – it will smooth out again! It may take up to an hour of whipping, but it’ll get there. Swiss meringue buttercream is notoriously temperamental; it’s also easy to fix, though it can require a bit of patience.

Once the buttercream is smooth and thick and completely emulsified, add the still slightly warm caramel, 1/8 tsp at a time. Adding more of the caramel at a time will cause the Swiss meringue buttercream to turn into a liquid soup. Should this happen, go ahead and incorporate all of the remaining caramel; refrigerate the buttercream “soup” for 30 minutes to an hour; then whip the buttercream until it becomes smooth and thick.

Use the buttercream immediately. Otherwise, store in the refrigerator for up to 3 days. After being in the refrigerator, the buttercream must be re-whipped to regain its creamy, spreadable consistency.

For the milk chocolate buttercream icing:
Beat the butter on high speed to soften it; scrape bowl. Add powdered sugar and beat on low until the powdered sugar begins to incorporate, then increase speed to medium-high and beat for 3 minutes. The powdered sugar may not fully incorporate with the butter; this is normal. Scrape bowl & add 2 TBS of cream and the 2 TBS of cocoa powder and beat on low speed until incorporated. Increase speed and beat on high for 2 minutes. Scrape bowl and add the melted chocolate (still barely warm) all at once; beat on high speed until completely blended. Scrape the bowl and beat for an additional 1 – 3 minutes on high speed to ensure all components are blended and smooth. If necessary, add additional cream, 1 TBS at a time, to thin icing to desired consistency.

Place one cake layer on a serving platter and spread with half the Swiss meringue buttercream. Cover with second cake layer and spread remaining Swiss meringue buttercream onto layer. Top with third cake layer and refrigerate cake to solidify the Swiss meringue buttercream, about 2 hours. When meringue is solidified, make the milk chocolate buttercream and ice top and sides of cake with milk chocolate buttercream. If desired, pipe decorative borders around top and bottom of cake with any remaining buttercream. (You may reserve 2 cups buttercream in advance for this purpose, if you wish.)

Keep cake in refrigerator to preserve the structural integrity of both the Swiss meringue buttercream and the milk chocolate buttercream. Both buttercreams will solidify while in the refrigerator. It is best to cut the cake while it is still cold and to then allow slices to sit at room temperature for about 45 minutes before eating. You’ll get the best flavour this way.

*I own only 2 8″ pans, so I divided the batter evenly between the two pans and the mixing bowl, baked the two layers, and cleaned one of the cake pans to use again for baking the third layer.

**It is imperative that you use salted butter to get the flavour of salted chocolate. If you would prefer a traditionally sweet chocolate buttercream, use unsalted butter.

***Use only bar chocolate or baking chocolate; chips have wax to help them keep their shape, and this wax causes grainy lumps in the finished buttercream.

****If you allow the melted chocolate to cool completely, it is likely to seize into small hard pieces when you add it to the buttercream. Should you be worried about this happening, wait until you’ve beaten together the butter, powdered sugar, and cocoa powder to melt the chocolate. Allow it to stand about 5 minutes or until barely warm, and incorporate it into the buttercream.

Sources: Cake, caramel, & Swiss meringue buttercream icing barely adapted from Annie’s Eats; milk chocolate buttercream is a Kitchenchantress Original


One thought on “Dark Mocha Cake with Caramel Swiss Meringue Buttercream and Salted Milk Chocolate Buttercream

  1. Pingback: Fudgy Mocha Cake with Raspberry Mousse, Chocolate Ganache, & Raspberry Swiss Meringue Buttercream | KitchEnchanted


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