Everyone knows I'm a cupcake girl, but since we were celebrating two birthdays this weekend, I thought a cake was in order. I decided to make a 3-tiered dark chocolate cake with mint buttercream filling and chocolate ganache frosting. Though that might sound super rich and decadent, it was actually perfectly balanced. The cake was moist and had just the right amount of chocolate. It wasn't overly rich at all. The filling was sweet, but that's what you would expect from buttercream, and you can always use as little or as much as you like. My layer was quite thick because we love mint. And the frosting was super creamy and smooth. I think that might have been my favorite part. Overall, I was very pleased with how this cake turned out, and it received rave reviews from the birthday boys!
Dark Chocolate Mint Cake
Serving size: 3 - 8 inch cakes
Dark Chocolate Cake:
2 1/4 cups all-purpose flour
2 1/4 cups granulated sugar
1 cup plus 2 tbsp. dark unsweetened cocoa powder
2 1/4 tsp. baking soda
1 1/2 tsp. baking powder
1 1/2 tsp. salt
6 tbsp. vegetable or canola oil
1 cup plus 2 tbsp. buttermilk
1 cup plus 2 tbsp. brewed coffee
3 large eggs, at room temperature
1 tbsp. vanilla extract
Mint buttercream filling:
3 sticks unsalted butter, at room temperature
5 1/2 cups confectioners' sugar, sifted
1 1/2 tsp. clear vanilla extract
3/4 tsp. peppermint extract
4-6 tbsp. heavy cream
Pinch of salt
Green food dye (optional)
Green food dye (optional)
Chocolate ganache frosting:
8 oz. bittersweet chocolate (60% cocoa) bars, finely chopped (such as Ghirardelli)
4 oz. semi-sweet chocolate bar, finely chopped (such as Ghirardelli)
1/4 cup very hot water
1/4 cup unsweetened cocoa powder
2 sticks plus 2 tbsp. (18 tbsp.) unsalted butter, at room temperature
1/3 cup plus 1 tbsp. confectioners' sugar
Pinch of salt
To prepare the cake, preheat the oven to 350°. Butter the bottom and sides of three 8 inch cake pans. Line the bottoms with parchment paper. Lightly flour the sides. In the bowl of an electric mixer fitted with a paddle attachment, mix the flour, sugar, cocoa powder, baking soda, baking powder, and salt together on low speed until well combined.
In a separate bowl, whisk the oil, buttermilk, coffee, eggs, and vanilla together. With the mixer on low, slowly add the wet ingredients to the dry ingredients, mixing just until combined. Scrape down the sides of the bowl with a spatula. Divide the batter evenly between the prepared cake pans. (A kitchen scale works great for this.)
Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean. Remove from the oven and let cool in the pan for 10 minutes. Invert onto a wire rack to cool completely.
To prepare the filling, in the bowl of an electric mixer fitted with a whisk attachment, beat the butter on medium-high speed until fluffy. Add the confectioners' sugar, 1 cup at a time, mixing well after each addition. Add the vanilla extract, peppermint extract, heavy cream, and salt. Whip until a smooth, fluffy frosting forms. Add additional cream as necessary to reach the desired consistency. Color with green food dye, if desired.
To prepare the frosting, melt the chocolate in a heat-proof bowl set over a pot of simmering water (double-boiler), stirring constantly. Set the bowl aside to cool to room temperature. In a separate bowl, stir the cocoa powder in the hot water until smooth. In the bowl of an electric mixer fitted with a whisk attachment, whip the butter, confectioners' sugar, and salt together on medium-high speed until light and fluffy, about 5 minutes. With the mixer on low, slowly add in the cooled chocolate until combined. Stir in the dissolved cocoa powder.
To assemble the cake, trim the cakes so that the tops and bottoms are flat using a serrated knife. Place one layer of cake on a cake stand. Place small pieces of parchment paper under the edge of the cake for easier clean-up. Place half (or the desired amount, I used a little less than half) of filling on top and smooth into an even layer using an off-set spatula. Place another cake layer on top. Add the remaining filling (or the desired amount, I used a little less than half) on top and smooth into an even layer. Place the third layer of cake on top, making sure the flattest end is up. Using a serrated knife, trim the sides of the cakes so that the edges are even. Place a large dollop of frosting on top and smooth into an even layer using an off-set spatula, allowing the excess to hang over the sides. Add additional frosting to the sides of the cake as needed and smooth out. Once the cake is covered with frosting and is mostly smooth, dip the off-set spatula into a cup of warm water and shake off the excess water. Re-smooth the sides and top of the cake with the wet spatula. Decorate the finished cake as desired.