Go Back

The Best Chocolate Peanut Butter Cake

Print Recipe
Rich Chocolate Cake Layers, the most heavenly peanut butter buttercream, chocolate ganache drips, and peanut butter cups!
Author Mandy Merriman

Ingredients

Chocolate Cake Layers

  • 3/4 cup buttermilk room temperature
  • 2/3 cup sour cream room temperature
  • 3 whole eggs room temperature
  • 1/3 cup vegetable oil
  • 1 Tablespoon vanilla
  • 1/4 cup cocoa powder
  • 1/4 cup flour
  • 1 15.25oz Dark Chocolate or Chocolate Cake Mix I prefer the taste and texture of Duncan Hines, but you can use anything similar.

Peanut Butter Buttercream

  • 1 1/2 cups (or three sticks) unsalted butter left out at room temperature for 10 minutes
  • 1 pinch salt
  • 1 Tablespoon pure vanilla
  • 2/3 cup Skippy creamy peanut butter
  • 1/4 cup heavy cream
  • 7-8 cups powdered sugar

Chocolate Ganache Drip

  • 2 cups chocolate candy melts
  • 1 cup heavy cream

Extras

  • 12 whole peanut butter cups chopped

Instructions

For the chocolate cake layers:

  • Preheat the oven to 325 degrees, and prep 2 8" cake rounds (or three 6" cake rounds) with a swipe of shortening and dust of flour. Set aside.
  • In a large bowl, whisk together all the ingredients except for the cake mix. Sift in the cake mix (don't overmix! This is a thick batter), and gently fold in until it's combined. Split the batter between the prepared cake rounds.
  • Bake for 27-32 minutes, or until the cake is finished baking in the center. Flip the cake rounds onto a wire rack to cool completely. Wrap the rounds up in plastic wrap and freeze until assembly. Frosting a cold/chilled/frozen cake is so much easier.

For the peanut butter buttercream:

  • In the bowl of a stand mixer fitted with a paddle attachment, whip up the butter until it's light and fluffy. Add in the salt, vanilla, creamy peanut butter, and whip it up until everything is thoroughly combined. With the mixer on low speed, add in the powdered sugar about 1/2 cup at a time. If the buttercream is looking too thick, add in another two tablespoons or so of heavy cream. If it's too thin, add in another 1/2 cup of powdered sugar.
  • Flip the mixer on the highest speed and let it whip up for at least 1-2 minutes until the texture is light and fluffy.

For the ganache:

  • Add the ganache and heavy cream into a medium bowl, and microwave for 30 seconds. Stir, then repeat. Stir again until it's smooth and creamy. Add to a squeeze bottle, then set side to slightly cool before adding to the cake. If the drip is too thick, stir in some more heavy cream. If it's too thin, toss in a couple more chocolate candy melts to help with consistency.

Assembly

  • With a cake turntable and cardboard cake round, add on a little bit of buttercream in the center of the round to act as glue. Place down the first cake layer, then spread on a generous layer of buttercream. Add on the next cake layer and then crumb coat the entire cake by adding on a thin layer of buttercream. Smooth the sides and top with a cake spatula and cake scraper.
  • Freeze the crumb coated cake for 5 minutes to set the cake. While the cake is chilling, hand-stir the buttercream with a wooden spoon to beat out any air bubbles and create a more smooth buttercream.
  • Slather on a final layer of buttercream and smooth out the sides with a cake scraper. Place the cake back into the freezer for 5 minutes to set the buttercream. Add on the ganache drip, then place on the peanut butter cups. Enjoy!