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Peanut Butter Sheet Cake with Chocolate Frosting

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Tender, rich peanut butter laced cake pieces with gooey peanut butter filling topped with fluffy chocolate buttercream frosting. This peanut butter sheet cake with chocolate frosting is easy to make, frost and serve!

Overhead of pieces of peanut butter sheet cake

Hi friends. It’s me. There’s this thing we need to talk about. It’s this cake, and it is going to change all the peanut butter loving lives everywhere.

We’re talking about rich peanut butter laced cake that’s fudgy in texture and not too sweet. Then we’re going to poke holes in the cake and smother it in more peanut butter so it gets all gooey and dreamy in the peanut butter valleys. 

And for the ultimate finish, we’re making fluffy, cloud-like chocolate buttercream.

fluffy chocolate buttercream spreading over peanut butter cake

And that’s just the taste folks. This cake recipe is so simple and no fuss. It only looks kinda fancy. 

One of my favorite parts is that you can just cut those squares out of the 9×13 pan and dish em out. So it makes transporting super easy, too. 

While this cake doesn’t come from a box, it’s still simple to put together that even a first time baker can pull off Pinterest perfect results.

overhead of peanut butter sheet cake in the pan with slice cut out

How to make peanut butter sheet cake

Sooo this is a peanut butter sheet cake that’s also a poke cake. By calling it a sheet cake, I mean that it’s baked and served in a 9×13 pan. A bakery style sheet cake is way way bigger, and while more cake is usually a good thing that is also A LOT of cake.

collage of procedure steps for peanut butter sheet cake with chocolate frosting

How many people does this peanut butter cake serve?

As mentioned just above, this cake is made in a tradition 9×13 pan. The best part about that is you can serve it right from the pan, so the serving size is really up to you.

Because the cake is pretty rich, smaller pieces are generally recommended. I like to cut this cake in 24 pieces (4×6), but you could go smaller if you wanted to. The crumb texture on peanut butter cake is very moist so it will stick together well while serving.

What’s a poke cake?

Bake a sheet cake. Let it cool 15 minutes. Poke holes in it. Cover it with something yummy – like peanut butter – that seeps into the holes.

Bam! You’ve got a poke cake, but more importantly you have cake.

spreading creamy peanut butter into poke cake

 

To poke the holes, my favorite thing to use is a strawberry huller.

What type of peanut butter should you use for peanut butter cake?

THIS is an important question. Peanut butter is super personal. Well, at least it is in this house.

It’s like the Romeo and Juliet of peanut butter. I’m over here on Capulet island with my father-in-law loving one kind and there’s all those other PB Montagues over there.

Personally, I’m team fresh ground PB (e.g. brands like Teddie’s). Where literally everyone else is team creamy smooth PB (e.g. brands like JIF, Skippy, etc.)  

However, when it comes to PB cake we can put the feud to rest without tragedy because the only love story here is cake.

To get the best results in texture and uniform baking you’re going to want to use a smooth, creamy style of peanut butter where the only doesn’t separate. 

We like the JIF all natural best. It melts without getting greasy and will bake without adding a gritty texture to the cake.

side view of peanut butter oozing out of peanut butter cake topped with chocolate frosting

Tips for making peanut butter sheet cake

Besides opting for a smooth peanut butter, there are a few tips that will help you avoid any bumps in the road on your journey to peanut butter and chocolate perfection.

  • If you don’t have buttermilk, you can make some real easy. Just check out the recipe notes.
  • Scrape down the bowl. This recipe has a decent amount of liquid, so scrape down the sides of your mixing bowl halfway through mixing.
  • LET IT COOL.
  • For the people in the back…LET IT COOL.

The cake needs to cool at least 15 minutes before you spread the peanut butter on top so it doesn’t melt into the actual cake. It will also need to completely cool before spreading the frosting. To do this you can just pop it in the refrigerator or even the freezer while you prepare the frosting.

slice of peanut butter cake on a plate with antique fork

If you only have 45 minutes to make a cake for a party, this might not be the best time to try to bang out a new recipe. While it’s faster than a layer cake recipe, you still need a little patience.

Take your time with this one, she’s worth it.

The fluffiest chocolate frosting

It’s weird right, 1 1/4 stick butter? I know. But it’s the perfect amount for this frosting.

This chocolate buttercream leaves the cake frosted with about 1/4 to 1/2 inch of pillowy chocolate frosting. The chocolate and the peanut butter is quite the butt kicking combination.

fluffy chocolate frosting spread onto sheet cake

By cutting back on butter and increasing the heavy cream, you’re balanced between a whipped cream frosting and a buttercream frosting. The beauty of it is that it will hold the great frosting texture of buttercream – meaning you can pipe with it – but the mouthfeel texture is fluffy like a whipped cream frosting.

It’s the best of both worlds.

What type of chocolate do you use for chocolate frosting?

Whatever type floats your boat darling! 

For this recipe, I used semi sweet, because that’s what I like. If you prefer milk chocolate, that will work the same, the final color of the frosting may be a touch lighter. If you prefer dark chocolate, same deal but the final color will be darker.

back lit photo pf a slice of peanut butter and chocolate cake

Tips for fluffy chocolate frosting

Let it cool. (OMG is there an echo in here or something?) 

But, no, really. I melted the chocolate for this, then took my dog for a quick walk.

The key to adding chocolate to frosting is that you need it to be melted but not hot. Otherwise, you’ll soften the butter too much.

You want to add the chocolate last. By building the rest of the frosting, you’re stabilizing the ingredients.

Lastly, make sure you give the sides of the bowl a good scrape and a final mix before taking the frosting out to to spread on the peanut butter sheet cake. This will prevent getting a random streak of gold/white frosting.

for sticking out of piece of peanut butter cake

More peanut butter and chocolate ideas

Are you obsessed with peanut butter? It’s pretty great! Here are some other recipes that might strike your fancy!

Did you make this recipe? Tell us about it in comments or tag #hungerthirstplay on social media with your pics!

overhead of peanut butter sheet cake in the pan with slice cut out

Peanut Butter Sheet Cake with Fluffy Chocolate Frosting

Rich peanut butter laced cake pieces with gooey peanut butter filling topped with fluffy chocolate buttercream frosting.  This peanut butter sheet cake is for all the peanut butter and chocolate lovers!
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Course: Cake
Cuisine: American
Keyword: cakes that travel well, easy sheet cake recipes, peanut butter and chocolate cakes, peanut butter cake, peanut butter cake for a group, peanut butter poke cake
Prep Time: 30 minutes
Cook Time: 36 minutes
Total Time: 1 hour 20 minutes
Servings: 24 servings
Calories: 336kcal
Author: Lauren

Ingredients

Peanut Butter Sheet Cake

  • 2 cups all purpose flour 298g
  • 2 cups granulated sugar 396g
  • ½ teaspoon baking soda
  • ¼ teaspoon salt
  • 1 cup water 250ml
  • 1 ½ sticks unsalted butter 170g, divided
  • ¼ cup canola oil 60ml
  • 1 cup creamy peanut butter 250g, divided
  • 2 eggs
  • ½ cup buttermilk* 120ml
  • 1 teaspoon pure vanilla extract

Fluffy Chocolate Buttercream Frosting

  • 1 12-ounce bag chocolate chips
  • 1 ¼ stick unsalted butter 176g
  • 2 cup confectioners sugar 250g
  • 1 teaspoon pure vanilla extract
  • ¼ cup heavy cream 60ml

Instructions

Peanut Butter Sheet Cake

  • Preheat the oven to 350°F and grease a 9x13 pan.
  • In a large bowl or the bowl of a standing mixer, whisk together the flour, sugar, baking soda, and salt.  In a small bowl, whisk the eggs, buttermilk and vanilla together, set aside.
  • Bring the water and 1 1/2 sticks unsalted butter to a simmer in a medium sized sauce pan.  Stir in 1/2 cup peanut butter and oil.  Stir until the peanut butter is completely incorporated then remove from the heat and add to the dry ingredients on low speed.  Increase the mixer speed to medium as the wet ingredients mix.
  •  Slowly add the remaining wet ingredients to the batter and beat on medium-high speed for 1 minute, scraping down the sides of the bowl half way through.  Pour the batter into the prepared 9x13 pan and bake for 33 to 36 minutes or until a toothpick inserted in the center of the cake comes out clean.
  • Let the cake cool for 15 minutes, then evenly spaced poke holes 3/4 of the way through the cake.  I did 4 holes across the width of the cake and 6 holes down the length.  (See notes for tools ideas to poke the holes.)
  • Spread the remaining 1/2 cup peanut butter over the cake while the cake is warm but not hot.  You need a little bit of warmth for the peanut butter to melt into the holes but you do not want it to melt into the cake.  Let the cake cool completely before frosting with chocolate buttercream - this can be done in the refrigerator to speed up the process.

Fluffy Chocolate Buttercream Frosting

  • While the cake is baking, melt 1 bag of chocolate chips in a double boiler* on the stove top.  Let cool for 15 to 20 minutes.  You want the chocolate to still be melted but not too warm so it will melt the butter in your buttercream.
  • In a standing mixer or with a hand mixer, beat the 1 1/4 stick butter on high speed until pale and fluffy.  Add the confectioners sugar and vanilla, slowly increase speed to medium-high as sugar incorporates.
  • Repeat with the heavy cream.  Once incorporated, increase speed to high and beat for 45 to 60 seconds until cream is fluffy like whipped cream - you will see the texture of the frosting change.  Add the chocolate and increase speed to medium-high as ingredients incorporate, scraping down the sides of the bowl when needed.
  • Using a spatula or frosting knife, spread the chocolate buttercream frosting over the cooled peanut butter sheet cake.

Notes

  • For the best texture and results use a traditional smooth, creamy peanut butter where the oil does not separate.  We like the JIF all natural peanut butter.  Other fresh ground brands (e.g. Teddie's - which I love, just not for this cake) will leave a gritty texture and you may get oil separation during baking.
  • If you do not have buttermilk, you can make it!  Pour 1/2 cup milk into a bowl, remove 1 tablespoon of the milk and add 1 tablespoon of lemon juice.  Stir and let it sit for 5 minutes.
  • Some tools you can use to poke your cake - strawberry huller, the round end of a wooden spoon or spatula, the handle of a piece of flatware and just spin it in a circle, a piping tip, or a very wide straw.
  • A double boiler system is easy to set up.  Add 1 to 2 inches of water to a medium size sauce pan and set a heat proof bowl over the pan.  The water should not touch the bottom of the bowl.  Add the chocolate chips to the bowl and bring the water to a simmer.  Stir until the chocolate is smooth and melty.  This system prevents burning the chocolate.

Nutrition

Calories: 336kcal | Carbohydrates: 37g | Protein: 5g | Fat: 20g | Saturated Fat: 9g | Trans Fat: 1g | Cholesterol: 45mg | Sodium: 110mg | Potassium: 99mg | Fiber: 1g | Sugar: 28g | Vitamin A: 388IU | Vitamin C: 1mg | Calcium: 19mg | Iron: 1mg

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Recipe Rating




Sara

Monday 19th of August 2019

Ooh! That icing looks to die for good. I have never made a sheet cake, but I really want to give it a go now that I saw this recipe.

Jordan

Monday 19th of August 2019

This is a peanut butter lovers' dream! My mom loves PB + chocolate - I can't wait to make this for her for her birthday next month.

Claire | The Simple, Sweet Life

Sunday 18th of August 2019

This cake looks absolutely divine, and I love that it's a sheet cake which means no multiple cake pans for washing, no stacking and easy slicing! Can't wait to give this a try.

Amy

Sunday 18th of August 2019

I’ve been on the lookout for a cake for my son’s birthday. This is perfect! It combines his favorite, chocolate and peanut butter! I love it! Thanks for sharing!

Carol Borchardt

Sunday 18th of August 2019

Chocolate and peanut butter together are simply heavenly and one of my favorite dessert combinations! Definitely pinning this as the dessert for my next get-together!