If you want a dessert that earns compliments every time, this Chocolate Peanut Butter Cake delivers.
I have made this cake recipe for birthdays, office parties, and even as a weekend treat. The combination of moist chocolate cake, rich fudge filling, and creamy peanut butter frosting works because it satisfies both chocolate and peanut butter lovers equally. You will learn how to create a stable, flavorful cake that holds up well for events and offers flexibility with or without the fudge filling.
Why This Peanut Butter Cookie Cake Style Works So Well
The structure reminds me of peanut butter cookie cakes, but with more depth. Instead of the usual dry crumb, this recipe stays moist for days. The boiling water and sour cream work together to lock in moisture, while the cocoa creates that deep chocolate base people expect in chocolate and peanut butter desserts.
Many peanut butter birthday cake recipes either lean too heavy on one flavor or dry out after a day. This one balances sweetness, saltiness, and texture.
The Ingredients Build the Foundation
The dry ingredients start with all-purpose flour, unsweetened cocoa powder, baking powder, baking soda, salt, and granulated sugar. The cocoa powder must be unsweetened for the right balance. Sweetened cocoa skews the flavor.
The wet ingredients include eggs, whole milk, vegetable oil, and vanilla extract. I always emphasize room temperature eggs and milk. They blend more smoothly and create a more even crumb.
Boiling water might seem odd, but it helps dissolve the cocoa fully, making the chocolate flavor richer.
Sour cream finishes the batter, adding both tenderness and slight tang, keeping the cake moist even after refrigeration.
Optional Fudge Filling: A Worthwhile Addition
For the fudge filling, you melt semi-sweet chocolate chips with heavy cream, butter, and vanilla extract. This creates a ganache-like layer that sits between the cake and frosting.
I often add this filling when I know the cake will sit out for a few hours at a party. The filling firms up slightly but stays creamy, offering an extra textural layer.
The Frosting Makes the Cake Stand Out
The peanut butter frosting requires creamy commercial peanut butter, unsalted butter, powdered sugar, heavy cream, vanilla extract, and a pinch of salt.
Natural peanut butter may seem tempting, but it separates too easily. I’ve tested both, and the stabilized texture of commercial brands always gives me smoother, fluffier results.
The heavy cream controls the consistency. Add it gradually to avoid over-thinning. A fluffy, spreadable frosting lets you create those decorative swirls easily.
Mixing Method: The Order Matters
Start by sifting the dry ingredients together. This step prevents clumps and distributes the leaveners evenly.
Whisk the sugar with eggs, milk, oil, and vanilla until smooth. Combining sugar with wet ingredients first helps dissolve it, preventing a gritty texture later.
Gently fold the dry mixture into the wet base. Do not overmix. Overmixing activates gluten, leading to dense layers.
Slowly add boiling water. The batter will seem thin, but this ensures a moist, tender crumb.
Fold in the sour cream last for stability and flavor balance.
Baking and Cooling: Timing Matters
Pour the batter into a greased 9×13-inch pan. Bake at 350°F for 35 to 40 minutes. Check with a toothpick for doneness.
Cool completely before adding filling or frosting. Rushing this step risks melting your fudge layer or frosting.
Assembling the Layers
If using the fudge filling, spread it gently over the cooled cake and let it firm up.
Once set, spread the peanut butter frosting generously across the surface. Use a spatula to create soft waves. The consistency holds its shape well but remains easy to slice.
Practical Comparison: Sour Cream vs. Buttermilk
In my notes, I’ve tested buttermilk as a substitute for sour cream. Buttermilk creates a slightly airier texture but lacks the same richness. Sour cream provides better moisture retention and a more stable crumb for layering. For this cake, I always return to sour cream.
Storage and Serving Suggestions
Store the cake covered at room temperature for up to two days. For longer storage, refrigerate for up to five days.
Before serving, allow refrigerated cake to sit at room temperature for 30 minutes. The frosting softens and the texture returns to its original tenderness.
I often serve this cake alongside a simple peanut butter dessert board for variety. You can find plenty of ideas for Peanut Butter Dessert Recipes if you want to expand the menu.
More Peanut Butter And Chocolate Dessert Inspiration
If you enjoy this cake, you may also like my Easy Peanut Butter Cake which offers a simpler version.
For cookie options, the Easy Peanut Butter Cookies recipe stays reliable even for beginners.
When I crave brownies, my Chocolate Peanut Butter Brownies satisfy every time.
If you’re curious about cake mix variations, my Chocolate Cake Mix Recipes Boxes Ideas article provides quick alternatives for busy days.
Join the Conversation and Pin for Later
I encourage you to save this recipe to your Pinterest board so you always have it ready for your next gathering.
Feel free to share your experience in the comments. I enjoy hearing how the recipe worked for you and am happy to answer questions.
Chocolate Peanut Butter Cake Recipe
This chocolate peanut butter cake features a rich, moist chocolate base with the option to include a smooth fudge filling. A fluffy, creamy peanut butter frosting adds a perfectly sweet and salty finish. It’s easy to make and consistently reliable for birthdays or celebrations.
Ingredients
- FOR THE CHOCOLATE CAKE
- 1 ¾ cups all-purpose flour
- ¾ cup unsweetened cocoa powder
- 1 ½ teaspoons baking powder
- 1 ½ teaspoons baking soda
- 1 teaspoon salt
- 2 cups granulated sugar
- 2 large eggs
- 1 cup whole milk
- ½ cup vegetable oil
- 2 teaspoons vanilla extract
- 1 cup boiling water
- ½ cup sour cream
- FOR THE FUDGE FILLING (optional but highly recommended)
- 1 cup semi-sweet chocolate chips
- ½ cup heavy cream
- 2 tablespoons butter
- 1 teaspoon vanilla extract
- FOR THE PEANUT BUTTER FROSTING
- 1 cup creamy peanut butter (not natural)
- ½ cup unsalted butter, room temperature
- 2 ½ to 3 cups powdered sugar
- ¼ cup heavy cream (add more for a lighter texture)
- 1 teaspoon vanilla extract
- Pinch of salt
Instructions
- PREHEAT AND PREP: Preheat the oven to 350°F (175°C). Grease a 9x13-inch baking pan and set aside.
- MIX DRY INGREDIENTS: In a large bowl, sift together the flour, cocoa powder, baking powder, baking soda, and salt to combine evenly.
- WHISK WET INGREDIENTS: In a separate large bowl, whisk the sugar, eggs, milk, vegetable oil, and vanilla extract until smooth and fully blended.
- COMBINE BATTER: Add the dry ingredients to the wet mixture and stir gently until just combined without overmixing.
- ADD BOILING WATER: Gradually stir in the boiling water to thin the batter. The mixture will be loose—this creates a moist cake texture.
- ADD SOUR CREAM: Fold in the sour cream until completely incorporated. The batter should be smooth and slightly glossy.
- BAKE THE CAKE: Pour the batter into the prepared pan and bake for 35 to 40 minutes, or until a toothpick inserted into the center comes out clean.
- COOL COMPLETELY: Remove the cake from the oven and let it cool fully in the pan on a wire rack before adding filling or frosting.
- MAKE THE FUDGE FILLING (OPTIONAL): In a medium saucepan over medium heat, melt the chocolate chips, heavy cream, and butter, stirring constantly until smooth. Remove from heat, stir in vanilla, and let cool slightly. Spread evenly over the cooled cake and let it set before frosting.
- MAKE THE PEANUT BUTTER FROSTING: In a large mixing bowl, beat the peanut butter and butter together until smooth and fluffy. Add powdered sugar gradually, alternating with the heavy cream, and beat until creamy. Mix in the vanilla and a pinch of salt. Adjust consistency with additional cream or sugar as needed for easy spreading.
- FROST THE CAKE: Once the cake and optional filling have cooled and set, spread the peanut butter frosting generously over the top. Use a spatula to create soft waves for a clean, decorative finish.
Notes
For best results, use commercial creamy peanut butter. Natural peanut butter may cause the frosting to separate. The fudge filling layer is optional but adds a rich contrast between the cake and frosting. Store cake covered at room temperature for up to 2 days or refrigerate for up to 5 days. Let it come to room temperature before serving for best texture.
