Peanut Butter Sheet Cake with Peanut Butter Frosting Recipe

If you’re the kind of person who can never resist a thick swipe of peanut butter on, well, anything, then you’re about to meet your next obsession: Peanut Butter Sheet Cake with Peanut Butter Frosting. This recipe packs a double punch of rich, nutty flavor in both the moist, tender cake and its sumptuous, glossy icing. The whole thing is surprisingly simple to pull together, with a level of indulgence that belies its unfussy process. Whether you’re feeding a birthday crowd or just want an excuse to bake something utterly irresistible, this Peanut Butter Sheet Cake with Peanut Butter Frosting is pure comfort in every bite.

Ingredients You’ll Need

The beauty of this recipe lies in its straightforward ingredients; each one is carefully chosen to amplify the flavor and texture of the cake and frosting. From creamy peanut butter to buttery richness and a convenient cake mix base, everything works together for a crowd-pleasing treat.

• Salted butter: Adds depth and a hint of savoriness that balances the sweet cake and intensifies the peanut butter flavor.
• Creamy peanut butter: The star of the show, lending luxurious nutty flavor and moisture to both cake and frosting.
• Milk (whole to skim): Keeps the cake tender and the frosting ultra-creamy—use whatever you have on hand.
• Vegetable oil: Ensures a soft, melt-in-your-mouth texture while keeping the cake moist for days.
• Vanilla extract: Adds warmth and enhances every other flavor in the cake and frosting.
• Eggs: Provide structure and essential richness, helping the cake rise beautifully.
• Yellow cake mix or Golden Butter cake mix: The secret to an incredibly easy and foolproof base—choose your favorite brand for the best results.
• Chopped peanuts: A crunchy finish that brings contrast and visual appeal atop the frosting.
• Powdered sugar: Creates a cloud-like, smooth frosting that pours beautifully over the cake.

How to Make Peanut Butter Sheet Cake with Peanut Butter Frosting

Step 1: Prep the Pan and Heat the Oven

Start by preheating your oven to 350F degrees. Give your 15×10-inch sheet pan or 13×9-inch baking pan a light greasing to ensure nothing sticks, because nothing breaks a baker’s heart like cake left behind in the pan!

Step 2: Melt the Wet Ingredients

In a large microwave-safe bowl, combine the butter, peanut butter, and milk. Pop it in the microwave on HIGH for about a minute. Stir it together until the butter’s totally melted and you have a glossy, puddly peanut butter mix. Now, stir in the vegetable oil and vanilla to deepen the flavors.

Step 3: Add and Beat the Eggs

Crack in your eggs. Give them a gentle beat in the center of the bowl first—think of it like giving them a head start so they blend in silky-smooth—then stir them into the rest of your peanut butter base.

Step 4: Incorporate the Cake Mix

Now, dump in the cake mix. Stir vigorously until everything is smooth and there are no hidden pockets of dry mix. Aim for about 45 good strokes—you want it fully combined but not overworked.

Step 5: Pour and Spread the Batter

Spoon the luscious peanut butter batter into your prepared pan. Use a spatula to nudge it into every corner and create an even layer. The cake bakes up perfectly whether you use a sheet pan or a standard 13×9, so you can use what you have and know it’ll turn out delicious.

Step 6: Bake Until Just Done

For a 15×10-inch sheet pan, bake for 13 to 15 minutes. Using a 13×9-inch pan? Bake for 19 to 21 minutes. Check with a toothpick inserted in the center—it should come out almost clean. Resist overbaking so you don’t lose that beautiful, tender crumb.

Step 7: Cool the Cake

Let your peanut butter sheet cake cool in the pan for at least 15 minutes. This slightly cooled surface is the secret to the perfect marriage of cake and frosting later, as the heat won’t melt everything into a puddle but will keep things spreadable.

Step 8: Prepare the Peanut Butter Frosting

In another large microwave-safe bowl, combine butter, peanut butter, and milk. Microwave for just under a minute, stirring until the butter is melted. Fold in vanilla and all that dreamy powdered sugar, then mix until you have a luscious, pourable (but thick) frosting that spreads like a dream.

Step 9: Frost and Finish

Pour your perfect Peanut Butter Frosting over the warm cake, using a spatula to guide it all the way to the edges. Finish with a generous sprinkle of chopped peanuts for the crunch factor. For super tidy slices, let your cake set for about an hour at room temperature or pop it in the fridge for 30 minutes.

How to Serve Peanut Butter Sheet Cake with Peanut Butter Frosting

Garnishes

For a classic finish, nothing beats a scattering of salty chopped peanuts on top. Try a drizzle of melted chocolate or a sprinkle of flaky sea salt if you want to go over-the-top. You can even add a swirl of whipped cream to up the nostalgia factor.

Side Dishes

This cake is rich and satisfying on its own, but it pairs wonderfully with a cold glass of milk, a mug of coffee, or even a scoop of vanilla ice cream. For a celebratory spread, serve it alongside fresh berries or a citrusy fruit salad to balance the peanut butter richness.

Creative Ways to Present

Slice the cake into squares and serve on cheerful platters for a casual gathering; or, use a small cookie cutter to make festive shapes for parties. Stack pieces with layers of frosting for a playful dessert sandwich, or pack individually wrapped slices into lunchboxes for a sweet surprise.

Make Ahead and Storage

Storing Leftovers

If you somehow manage to have leftovers, simply cover the cake tightly with foil or transfer slices to an airtight container. It keeps beautifully at room temperature for up to three days, and the frosting stays smooth and dreamy.

Freezing

This Peanut Butter Sheet Cake with Peanut Butter Frosting freezes like a charm! Individually wrap slices in plastic wrap, then place them in a zippered bag or airtight container. Freeze for up to two months—just thaw at room temperature before enjoying.

Reheating

If you love cake a little warm, pop an individual slice into the microwave for about 10–15 seconds. The frosting will get glossed up and extra creamy—total comfort on a chilly afternoon.

FAQs

Can I use chunky peanut butter instead of creamy?

Absolutely! Chunky peanut butter adds a fun, extra-crunchy texture to both the cake and Peanut Butter Frosting. Just be sure to stir well to distribute those tasty pieces throughout.

Is it possible to make this recipe gluten-free?

Yes, simply substitute your favorite gluten-free yellow cake mix. Follow the rest of the directions without any changes—just check the cake for doneness as baking times may vary slightly.

Can I double the recipe for a crowd?

Definitely! You can double all ingredients and use a larger, rimmed baking sheet, or bake two separate cakes. It’s a perfect solution for parties, potlucks, and bake sales.

How long does the Peanut Butter Sheet Cake with Peanut Butter Frosting stay fresh?

The cake keeps its moist crumb and luscious frosting for about three days at room temperature (covered), or up to a week if refrigerated. Any longer, and the freezer is your best bet.

Does the frosting firm up enough for neat slicing?

Yes! As it cools, the peanut butter frosting sets up beautifully, especially after standing for an hour at room temperature or after a quick chill. This makes slicing and serving neat, clean pieces a breeze.

Final Thoughts

There’s something truly special about serving up a big, cheerful pan of Peanut Butter Sheet Cake with Peanut Butter Frosting—it’s the kind of dessert that just makes people happy. Give it a try and see for yourself; your kitchen will smell amazing, and you’ll have a new family favorite that’ll disappear before you know it!

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