There are some desserts that simply disappear the moment you set them out. This Peanut Butter Sheet Cake with Peanut Butter Frosting is one of them. Rich, moist, and packed with peanut butter flavor in every layer, this cake is a dream come true for peanut butter lovers.
What makes this cake so wonderful is its simplicity. Starting with a box of yellow cake mix as the base, you can create a homemade-tasting sheet cake that feeds a crowd with minimal effort. The cake is tender and perfectly moist, thanks to the addition of sour cream and peanut butter. Topped with a creamy, decadent peanut butter frosting that sets into a silky layer, every bite is pure indulgence.
Sheet cakes are the ultimate dessert for gatherings. They are easy to transport, simple to slice, and always satisfy a crowd. Whether you are bringing this to a potluck, a birthday celebration, or simply treating your family on a weekend, this Peanut Butter Sheet Cake is guaranteed to be a hit.
Why You Will Love This Recipe
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Double the Peanut Butter: Peanut butter in the cake and peanut butter in the frosting means rich, nutty flavor in every bite.
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Perfect for a Crowd: Baked in a sheet pan, this cake serves 12 to 15 people easily.
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Incredibly Moist: The combination of sour cream and butter creates a tender, never-dry crumb.
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Easy to Make: A boxed cake mix shortcut makes this recipe simple, while the homemade frosting elevates it to something special.
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Transportable: Sheet cakes are sturdy and easy to transport, making them ideal for parties, potlucks, and bake sales.
Peanut Butter Sheet Cake with Peanut Butter Frosting
Prep Time: 15 minutes | Bake Time: 25 to 30 minutes | Total Time: 1 hour
Servings: 12 to 15
This peanut butter sheet cake is rich, moist, and bursting with peanut butter flavor. A simple yellow cake mix serves as the base, enhanced with peanut butter, sour cream, and butter for a homemade taste. Topped with a creamy peanut butter frosting, this cake is a crowd-pleaser for any occasion.
Ingredients
For the Cake:
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1 box (15.25 ounces) yellow cake mix
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4 large eggs
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½ cup (1 stick) unsalted butter, softened
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1 cup creamy peanut butter
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1 cup sour cream
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½ cup milk
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1 teaspoon vanilla extract
For the Peanut Butter Frosting:
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½ cup (1 stick) unsalted butter, softened
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½ cup creamy peanut butter
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3 to 4 cups powdered sugar
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¼ cup milk (plus more as needed)
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1 teaspoon vanilla extract
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Pinch of salt
For Garnish (Optional):
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Chopped peanuts
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Mini chocolate chips
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Crushed peanut butter cups
Instructions
Step 1: Preheat and Prepare
Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking pan or line it with parchment paper. Set aside.
Step 2: Mix the Cake Batter
In a large mixing bowl or the bowl of a stand mixer, combine the yellow cake mix, softened butter, creamy peanut butter, sour cream, milk, eggs, and vanilla extract. Beat on medium speed for 2 to 3 minutes, until the batter is smooth, creamy, and well combined. Scrape down the sides of the bowl as needed.
Step 3: Bake
Pour the batter into the prepared baking pan and spread it evenly with a spatula. Bake for 25 to 30 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs. The edges should be lightly golden and the center should spring back when gently pressed.
Step 4: Cool
Remove the cake from the oven and place it on a wire rack. Allow the cake to cool completely in the pan before frosting, about 1 hour.
Step 5: Make the Frosting
While the cake is cooling, prepare the frosting. In a large mixing bowl, beat the softened butter and creamy peanut butter together until smooth and creamy, about 2 minutes. Add the vanilla extract and salt. Gradually add the powdered sugar, 1 cup at a time, alternating with small amounts of milk, beating well after each addition. Continue until the frosting is thick, spreadable, and smooth. Add more milk if needed for desired consistency.
Step 6: Frost the Cake
Once the cake is completely cool, spread the peanut butter frosting evenly over the top. Use an offset spatula or the back of a spoon to create swirls or a smooth finish.
Step 7: Garnish and Serve
If desired, sprinkle with chopped peanuts, mini chocolate chips, or crushed peanut butter cups for added texture and visual appeal. Slice into squares and serve.
Tips for the Perfect Peanut Butter Sheet Cake
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Use Room Temperature Ingredients:Allow the butter, eggs, and sour cream to come to room temperature before mixing. This ensures a smooth, well-emulsified batter and a tender crumb.
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Do Not Overmix: Mix the batter just until combined and smooth. Overmixing can develop too much gluten, resulting in a dense cake.
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Check for Doneness: Start checking the cake around the 25-minute mark. A toothpick inserted in the center should come out clean or with a few moist crumbs—not wet batter.
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Cool Completely: Allow the cake to cool fully before frosting. If the cake is even slightly warm, the frosting will melt and become runny.
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Adjust Frosting Consistency: For a thicker, stiffer frosting, add more powdered sugar. For a softer, more spreadable frosting, add a little extra milk.
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Store Properly: This cake stays moist and delicious for days when stored covered at room temperature.
Variations and Additions
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Chocolate Peanut Butter Cake: Add ½ cup of mini chocolate chips to the batter for pockets of chocolate in every bite.
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Reese’s Cup Cake: Fold in 1 cup of chopped Reese’s peanut butter cups into the batter and sprinkle more on top of the frosting.
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Chocolate Frosting: Swap the peanut butter frosting for a rich chocolate buttercream for a classic peanut butter and chocolate combination.
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Cream Cheese Peanut Butter Frosting: Replace half of the butter with cream cheese for a tangy, creamy variation.
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Salted Peanut Butter: Add ½ teaspoon of flaky sea salt to the frosting for a sweet and salty contrast.
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Gluten-Free Version: Use a gluten-free yellow cake mix and ensure all other ingredients are gluten-free.
What to Serve with Peanut Butter Sheet Cake
This rich, decadent cake is delicious on its own, but it pairs beautifully with:
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A tall glass of cold milk
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A scoop of vanilla bean ice cream
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A drizzle of warm chocolate sauce
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Fresh banana slices for a classic peanut butter and banana combination
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A cup of hot coffee or espresso
Storage and Freezing
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Room Temperature: Store the cake covered at room temperature for up to 4 days. The frosting will remain soft and creamy.
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Refrigerator: If your kitchen is warm, the cake can be refrigerated for up to 1 week. Bring to room temperature before serving for the best texture.
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Freezer: This cake freezes beautifully. Wrap individual slices or the whole unfrosted cake tightly in plastic wrap and aluminum foil. Freeze for up to 3 months. Frost after thawing for best results.
Why This Recipe Works
This recipe takes the convenience of a boxed cake mix and elevates it with ingredients that add moisture, richness, and depth of flavor. The addition of peanut butter to the batter infuses every bite with nutty flavor, while sour cream ensures a tender, moist crumb. Butter adds richness, and milk helps create a smooth, pourable batter.
The frosting is a classic peanut butter buttercream—creamy, sweet, and perfectly balanced with a pinch of salt to enhance the peanut butter flavor. Together, the cake and frosting create a dessert that tastes entirely homemade with minimal effort.
Nutritional Information
Please note that values are estimates and will vary based on specific ingredients and portion sizes.
Per serving (based on 15 servings):
| Nutrient | Amount |
|---|---|
| Calories | 450–550 |
| Protein | 8–10g |
| Carbohydrates | 55–65g |
| Fat | 25–30g |
| Saturated Fat | 12–15g |
| Sugar | 40–50g |
| Sodium | 350–450mg |
Conclusion
Peanut Butter Sheet Cake with Peanut Butter Frosting is the kind of dessert that brings people together. It is rich, comforting, and unapologetically indulgent—the perfect treat for birthdays, potlucks, or any time you need a little something sweet. With its moist crumb, double dose of peanut butter, and creamy frosting, this cake is sure to become a favorite.
Whether you are making it for a crowd or simply treating your family, I hope this recipe brings as much joy to your table as it has to mine.
If you give this recipe a try, please leave a comment below. I would love to hear how it turned out for you.