Mint and chocolate are combined in this beautiful layer cake inspired by kintsugi, the Japanese art of repairing broken pottery, as well as my latest kitchen refresh with my sponsor, Café Appliances—jump to the recipe. As always all thoughts and opinions are my own, and thank you for supporting the sponsors that keep Hummingbird High up and running!
Why a mint chocolate cake?
Earlier this week, I shared with you the results of my kitchen refresh—I’d updated its color scheme to be brighter and more vibrant, and swapped out my boring stainless steel appliances with these beautiful Matte Black Café Appliances. Not only did the changes feel like I had a brand new kitchen, but I also found myself feeling creatively inspired by my kitchen’s new look. I found myself wanting to create a cake specifically to celebrate its new personality, similar to how I’d made a cake that looked like the American flag for the 4th of July, or how I’d made a galaxy cake to announce my cookbook’s launch team.
Because I’d chosen a vibrant green color for my cabinetry and the dramatic Matte Black Café Appliances, the flavors of mint and chocolate immediately came to mind. Mint and chocolate is a classic flavor combination, but I only ever see it used in ice cream and cookie recipes—it’s rare to find a mint chocolate cake. I decided to fill this void on the internet with my own recipe, making sure to make it a beautiful layer cake that would honor my beautiful new kitchen too.
What is kintsugi?
In addition to the new green and black colors, however, my kitchen also has lots of brushed metal elements: specifically, brushed brass hardware for my cabinets and Brushed Copper hardware for my appliances (Café Appliances allows you to customize your appliance hardware—isn’t that neat?!). I wanted to find a way to also incorporate these beautiful elements into my cake.
Last year, however, I made this ube layer cake inspired by a trend that was hitting the wedding cake industry hard: decorating cakes to look like kintsugi ceramic wares. What exactly is kintsugi? Kintsugi is a Japanese word that roughly translates to “golden joinery”, and refers to the art of repairing broken pottery by joining the broken pieces with a gold-dusted paint. The end result is absolutely beautiful, and results in whole plates, bowls, and mugs with gold veining throughout their surfaces. Take a look; isn’t it neat? The best part is that every resulting piece is absolutely unique.
To translate this to my cake, I made two batches of colored frosting: green and white, which I then used to decorate the cake in an ombre style. After that, I used tweezers to apply crumpled pieces of edible gold leaf where the colors meet. It looks especially good if you apply the two separate colors unevenly throughout the cake—that means you can make a crazy pattern with the gold leaf, giving it an authentic kintsugi effect.
All of this, of course, is made much easier if you have a reliable buttercream frosting recipe.
How to Make Swiss Meringue Buttercream
Typically, my favorite type of frosting is American buttercream frosting: not only is it delicious (it tastes like the frosting from your favorite childhood cake!), but it’s incredibly simple to make and comes together so quickly. Unfortunately, American buttercream frosting isn’t the best when it comes to decorating and styling high-design cakes like this one—for that, you gotta stick with what the pros use for weddings and special events: Swiss meringue buttercream.
Once you make Swiss meringue buttercream, it’s a dream to work with. It’s incredibly soft and silky, spreading and piping beautifully and cleanly. Unfortunately, it’s a bit of a process to make. Swiss meringue buttercream instructs you to first cook sugar and egg whites to an exact temperature; you then whip this mixture into a meringue to use as a base for the buttercream frosting.
With my old range, heating the sugar and egg whites together TOOK forever. Because not only do you have to cook the mixture to a specific temperature (160°F, as a matter of fact) , but you also have to do it slowly in a double boiler—or else, the egg whites will cook into a scramble before it hits the right temperature! I think my old range didn’t have enough power or something, because it literally took like 30 minutes to get my egg whites to 160°F. However, one of my favorite things about my new Café range is the fact that it has a professional, high-heat burner—that baby is so strong that it literally cut the time it took to cook my egg whites down to around 12 minutes (even in a double boiler, too)! Color me impressed.
Best Mint Chocolate Cake Recipe Tips
- The chocolate cake recipe comes from my upcoming cookbook, Weeknight Baking. In the book, the recipe makes two layers, but it’s possible to bake it in three pans like I did for this recipe to get a three layer cake. Just make sure you divide the layers evenly between each pan (something I failed to do for this cake, oopsy!)—I talk about how to do this more in my book, but it’s best to use a digital scale to actually weigh out the amount of batter that goes in each pan (which I did not do for this cake, since my scale ran out of batteries when I was making this cake ????). I’ve included the approximate weight measurement of batter that goes into each cake pan.
- The Swiss meringue buttercream frosting is adapted from my friend Tessa of Style Sweet and her awesome cookbook, Layered. Now, I don’t recommend this often, but when making the frosting, I highly encourage you to add mint flavoring a half teaspoon at a time and taste as you go—mint extract can be a VERY overpowering flavor, and it’s one that is pretty relative to the person’s palette. That is, what tastes subtle to some will taste very, very toothpaste-y and gross to others. I use a whopping 1 tablespoon of mint extract in this frosting—which is a LOT. The frosting on its own tasted super intense and too much, but was really, really lovely and subtle when paired with the chocolate cake. But again, it’s really important to use your judgement and taste as you go with this recipe!
- Like I said—Swiss meringue buttercream can be finnicky. Make sure your butter is completely at room temperature (that is, between 65°F to 70°F) before adding it to the meringue. If it’s too melty, your Swiss buttercream will turn out like soup—but no worries, we can fix this! Simply stick it in the fridge for 15 minutes, before beating again. Alternatively, if your butter is too cold, the buttercream can curdle. If you find this happening, scoop out ¼ cup of the frosting (there’s no need to be precise—you can just eyeball it), microwave it for 15 seconds, then add it back to the frosting while beating it on medium-high speed. That should help bring the rest of the buttercream down in temperature and prevent any further curdling!
Mint Chocolate Kintsugi Cake Recipe
- Special Equipment: a digital candy thermometer, tweezers
For the Chocolate Cake
- 2 cups 8 ounces cake flour
- 2 cups 14 ounces granulated sugar
- ¾ cup 2.25 ounces natural unsweetened cocoa powder, sifted if lumpy
- 2 teaspoons baking soda
- 1 teaspoon baking powder
- 1 teaspoon kosher salt
- 1 cup 8 ounces buttermilk
- ½ cup 4 ounces canola oil
- 2 large eggs
- 2 teaspoons pure vanilla extract
- 1 cup 8 ounces very hot coffee
- For the Mint Swiss Meringue Buttercream
- 8 ounces around 1 cup large egg whites (from around 10 large eggs)
- 2 cups 14 ounces granulated sugar
- A pinch of kosher salt
- 2 cups 16 ounces unsalted butter, at room temperature
- 1 tablespoon peppermint extract
- green food coloring
- edible gold leaf
For the Chocolate Cake
- Position a rack in the center of the oven and preheat the oven to 350°F. Generously spray three 8-inch cake pans with cooking spray and line the bottom of each with a parchment paper circle. Spray the parchment, too.
- In a medium bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt.
- In a large bowl, whisk together the buttermilk, oil, eggs, and vanilla. Gradually whisk in the dry ingredients until just combined. Slowly pour in the coffee. The batter will be fairly runny; use a rubber spatula to scrape down the bottom and sides of the bowl. Use the rubber spatula to finish mixing until smooth and well combined, 2 to 3 minutes more.
- Divide the batter evenly between the pans; if using a digital scale, note that this recipe makes around 44 ounces of batter—pour 14.6 ounces of batter into each cake pan. Bake for 25 to 30 minutes. When done, the top of the cake should bounce back when gently pressed and a skewer inserted into the center of the cake should come out with a few crumbs attached. Cool completely in the pans on a wire rack before frosting.
For the Mint Swiss Meringue Buttercream Frosting
- Whisk together the egg whites and the sugar in the top pan of a double boiler (or, make a homemade version by placing a heatproof bowl over a sauce pan filled with 2 to 3 inches of simmering water, ensuring that the bottom of the bowl does not touch the water). Cook over medium-high heat, whisking intermittently, until the mixture registers 160°F on a candy thermometer.
- Once the mixture reaches 160°F, immediately pour into the bowl of a stand mixer fitted with a whisk attachment. Whisk on high speed for 8 to 10 minutes, or until the mixture has turned into a meringue that holds medium-stiff peaks. When done, the outside of the mixer bowl should be at room temperature and no residual heat should be escaping the meringue out of the top of the bowl. Stop the mixer and use a rubber spatula to scrape down the whisk and the bottom and sides of the bowl. Replace the whisk attachment with the paddle attachment.
- With the mixer on low speed, add the butter, a few tablespoons at a time. Once incorporated, increase the mixer speed to medium-high and beat until the buttercream is silky smooth, 3 to 5 minutes. Use a rubber spatula to scrape down the paddle and bottom and sides of the bowl. With the mixer on medium-low, add the peppermint extract, ½ teaspoon at a time, tasting the buttercream after every addition until satisfied with the flavor.
- Scrape out about ⅔rds of the buttercream into a medium bowl and set aside. Add 2 to 3 drops of green food coloring to the remaining buttercream and beat on medium-low until a uniform green.
- Once the layer cakes have cooled completely, use the white batch of the Mint Swiss Meringue buttercream to assemble the cake. Use around ⅔ cup of frosting between each cake layer, and cover the cake with a smooth, thin layer of frosting. You’ll likely have a lot of buttercream leftover—this is ideal, as you’ll need this later in the decorating process. Transfer to the refrigerator to chill for at least 1 hour to allow the buttercream to set.
- Once the buttercream has set, remove from the refrigerator. Cover the bottom half of the cake with green batch of buttercream, and the top half of the cake with the remaining white buttercream. Use an offset spatula to smooth the frosting around the cake completely.
- Use tweezers to carefully apply a small tear of gold leaf at the border where the green and white buttercream meet. As you place the gold leaf on the cake, the gold leaf will wrinkle to give the cake the kintsugi effect. Continue tracing the border of the two colors with gold leaf until complete.