If you love chocolate, peanut butter, and a beautifully bare cake, this chocolate-peanut butter cake dessert filled with peanut butter buttercream, drizzled with dark chocolate sauce + peanut butter sauce, and topped with chocolate shavings is for you! The chocolate cake is extra rich and fudgy, almost like a brownie, and not too sweet at all. It’s because dark cocoa powder is used along with melted dark chocolate. Brewed coffee is also added into the cake batter just to heighten the chocolate taste.
There are several components needed to make this cake but you can definitely make them ahead and just assemble the cake on the day it will be served. The rich decadent chocolate cake is still moist and fudgy after 5 days!
- As the chocolate cake is soft and not too thick, cutting it in half (horizontally) might be a bit of a challenge. After cake has been cooled, wrap it in cling film and and put in the fridge for at least 30 minutes before slicing them. This step keeps the crumbs away and reduces the chance of breaking them. Levelling and torting is easier with cakes if they are cold. I use a cake leveler but a sharp bread knife will get the job done too.
- Test the consistency of your buttercream. If the buttercream is too thin, it will not hold its shape well and can run. If buttercream too thick it may be too hard to squeeze or may crack once dry. Add in cream 1 teaspoon at a time if you need to thin out your buttercream a bit. Use liquid sparingly as a small amount can completely change the consistency of buttercream.
- When making the buttercream, do not add all the icing sugar all at once. Icing sugar makes the buttercream stiff so add more if you find your icing too thin. Add them in increments until you have achieved your desired consistency and taste as well. We don’t want an overly sweet buttercream.
Chocolate-Peanut Butter Cake
For the chocolate cake:
- 84 grams (1/2 cup) all-purpose flour
- 19 grams (1/4 cup) dark cocoa powder
- 3 grams (1/2 teaspoon) baking soda
- 2 grams (1/2 teaspoon) baking powder
- 2 grams (1/4 teaspoon) salt
- 38 grams (1/4 cup) dark chocolate, coarsely chopped (I used 70% cocoa)
- 57 grams (1/4 cup) unsalted butter, melted
- 117 grams (1/2 cup) granulated sugar
- 33 grams (2 1/2 tablespoons) egg
- 5 grams (1 teaspoon) vanilla extract
- 123 grams (1/2 cup) buttermilk
- 39 grams (2 1/2 tablespoons) strong brewed coffee
For the peanut butter sauce:
- 86 grams (1/3 cup) smooth peanut butter
- 61 grams (1/4 cup) heavy cream
- 28 grams (4 teaspoons) light corn syrup
For the peanut butter frosting:
- 341 grams (1 1/2 cups) unsalted butter, at room temperature
- 23 grams (1 1/2 tablespoons) heavy cream
- 9 grams (2 teaspoons) vanilla extract
- 1 gram (1/8 teaspoon) salt
- 32 grams (2 tablespoons) peanut butter
- 170-270 grams (1 1/2 - 2 1/4 cups) confectioner's sugar
For assembling the cake:
- 100 grams (about 1/3 cup) dark chocolate sauce (see Note 1 for recipe link)
- 35 grams (about 1/4 cup) chocolate shavings
Make the cake
- Heat oven to 350 F. Grease and line 1 8-inch round pan (at least 2 inches high) and dust the pan lightly with cocoa powder. Tap out any excess. Set aside.
- In a medium bowl, combine the flour, cocoa powder, baking soda, baking powder, and salt. Stir with a whisk and set aside.
- Add the dark chocolate to a small heatproof bowl and set it over a pot of barely simmering water. Stir continuously until melted and smooth. Remove from heat. Set aside to cool.
- Using a stand mixer fitted with paddle attachment or a handheld mixer, beat the butter and sugar together on medium-low speed until light and fluffy. Add the eggs, one at a time, mixing well after each addition. Scrape down the sides of the bowl as needed. Add in the vanilla and the melted chocolate and mix well until well incorporated.
- Set the mixer to low speed, gradually add half of the flour mixture, then the buttermilk, coffee, and then the remaining half of the flour mixture. Beat until just combined. The batter should be thick.
- Pour the batter in pan. Use an offset spatula to spread the batter all the way to the edges of the pan and smooth out the surface. Bake for 30-40 minutes, or until a toothpick inserted into the center comes out with only a few dry crumbs. Cool the cake in the pan for 10 minutes, then transfer into a wire rack to cool completely.
- Once cooled, peel the parchment paper off, wrap in cling film, and store in the fridge for at least 30 minutes.
Make the peanut butter sauce
- Combine all the ingredients in a small sauce pan. Cook over medium heat while stirring constantly, until melted and incorporated, around 3 minutes. Once the sauce is smooth, remove from heat. Avoid cooking too long or the sauce will become very thick. Cool sauce slightly before using. (See Note 3)
Make the frosting
- In a stand mixer fitted with paddle attachment or with an electric hand mixer, beat the butter on medium-high speed until smooth. Add the cream vanilla, salt, and peanut butter. Continue to beat until well incorporated.
- Add 1/3 of of confectioner's sugar, beat on medium-low speed until most of the sugar has moistened. Gradually add in the remaining sugar, 1/4 cup at a time. Beat again on medium-low speed until the sugar has moistened. Turn the speed up to medium-high and beat until light and fluffy. You may need more or less confectioner's sugar depending on how soft your butter is. Scrape down the sides of the bowl as needed. (See Note 2)
Assemble the cake
- Place the peanut butter buttercream in a large piping bag fitted with a large round coupler. Place the chocolate sauce and peanut butter sauce in a plastic squeeze bottle. Make some chocolate savings by using a vegetable peeler or knife to shave flat, thin shavings from a room-temperature block of chocolate.
- Remove the cake from fridge and place onto a cutting surface. Split the cake into 2 even layers using a cake leveler or a bread knife. place the bottom layer onto a serving platter. Pipe big blobs of the buttercream on top of the cake. Add the second cake layer and pipe blobs of buttercream again on top.
- Drizzle some peanut butter sauce and dark chocolate sauce, and then top with chocolate shavings.