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Chocolate Peanut Butter Cake Recipe

Excerpted from ‘I’ll Bring the Cake: Recipes for Every Season and Every Occasion’

two pieces of three-layer chocolate peanut butter cake on paper plates, each with fork on them; jar of peanut butter with spoon in it is in between the plates; peanut butter cup next to bottom plate

Mandy Merriman


This cake is by far my most popular. I’ve had repeated requests for it from friends and family, and it’s a number one favorite with my readers across the globe. It’s one of my favorite cakes of all time, too, so I don’t blame them. Stripes of thick whipped peanut butter and cocoa buttercreams envelop this chocolate cake. I always add mini chocolate chips along the bottom and on top for texture, and it doesn’t seem complete without a few Reese’s Peanut Butter Cups to crown this one as the king of cakes.



Chocolate Cake

  • ¾ cup buttermilk (room temperature)
  • 2/3 cup sour cream (room temperature)
  • 3 large eggs (room temperature)
  • 1/3 cup vegetable oil
  • ¼ cup mini chocolate chips
  • 1 tablespoon pure vanilla extract
  • ½ cup cocoa powder
  • 1 box dark chocolate cake mix

Peanut Butter Buttercream

  • 1 batch vanilla buttercream (recipe follows)
  • 2/3 cup creamy peanut butter (I prefer Skippy)
  • ½ cup cocoa powder

Vanilla Buttercream

  • 3 sticks (1½ cups) unsalted butter
  • Pinch of salt
  • 1 tablespoon pure vanilla extract
  • ¼ cup heavy cream (plus more if needed)
  • 7 to 8 cups powdered sugar

For Decorating

  • Reese’s Peanut Butter cups
  • Mini chocolate chips
  • Stripe cake comb
  • Piping bag
  • Wilton 1M piping tip



For the Chocolate Cake

Preheat the oven to 325°F, then prep three 6-inch round cake pans with a swipe of shortening and dusting of flour to prevent sticking. In a large bowl, whisk together the buttermilk, sour cream, eggs, oil, mini chocolate chips and vanilla until thoroughly combined. Sift in the cocoa powder and cake mix and whisk until just combined. Do not overmix. Split the batter evenly among the prepared pans. Bake for 30 to 32 minutes, until the center is baked through. Let the cakes cool in the pan for a minute before flipping them out onto a wire rack to cool completely. Wrap and freeze the cakes before assembly.

For the Vanilla Buttercream

In the bowl of a stand mixer fitted with a paddle attachment, beat the butter on medium speed until it’s light and fluffy. Add the salt, vanilla, and heavy cream and beat again until thoroughly combined. Scrape down the sides of the bowl. With the mixer on low speed, add the powdered sugar about ½ cup at a time. Add a little more heavy cream if needed, then flip the mixer to high speed and beat until the buttercream is lighter in color and texture, about 2 minutes.

For the Peanut Butter Buttercream

In the bowl of a stand mixer fitted with a paddle attachment, beat the buttercream and peanut butter until evenly combined, then scrape down the sides with a spatula. Transfer 2 cups of the buttercream to a separate bowl and stir in the cocoa powder until combined. Transfer to a piping bag without a piping tip. Set aside.

To Assemble

Place a cardboard cake round on a cake turntable. Dot a little bit of buttercream in the center of the round and spread it out with an angled icing spatula. Place the first chilled cake layer in the center. Add a layer of buttercream. Place the next cake layer on top, then repeat, making sure to line the layers up evenly. After adding the top cake layer, crumb coat the cake by spreading a thin layer of buttercream around the entire cake. Freeze for 2 minutes to set the buttercream. Using a wooden spoon, beat out any air bubbles in the remaining buttercream. Finish frosting the cake as desired or follow the decorating instructions below.

To Decorate the Cake

Spread a final layer of buttercream around the entire cake, using a stripe cake comb to make clean indents on the side of the cake. The crisper the indents, the cleaner the stripes will be later on. Freeze for at least 10 minutes so that the buttercream is very firm. When the stripe indents are firm to the touch, pipe the cocoa buttercream in the indents and then immediately scrape the sides of the cake with a flat cake scraper. Apply a little bit of pressure and scrape until the clean stripes start to show through. Add the remaining peanut butter and cocoa buttercreams to a piping bag fitted with a Wilton 1M tip. Pipe a buttercream swirl on top of the cake along the outside rim, then place a peanut butter cup on the top of the cake. Sprinkle some mini chocolate chips in the center. Add small chocolate chips along the bottom rim of the cake.

Tip: You won’t need to make two separate buttercreams for these gorgeous stripes. You’ll just reserve a little of the peanut butter buttercream and whip it up with some cocoa powder. You only need enough cocoa buttercream to fill in the indents between the stripes.

Bake With Mandy

Two more recipes from I’ll Bring the Cake for AARP members to try:

Blueberry Shortbread Crumble Cake

With a fresh blueberry cake baked right onto a shortbread crust, a fresh blueberry filling, blueberry buttercream and a shortbread crumble on top, you might already be headed out the door to find as many blueberries as you can.

Circus Animal Cookie Cake With Almond White Chocolate Buttercream

This cake, with a strong almond and white chocolate flavor throughout and pink and white exterior, tastes and looks just like circus animal cookies. 


Read About Mandy Merrimans cookbook, I’ll Bring the Cake.

book with words i'll bring the cake on cover and picture of light pink cake with blueberry designs on it


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