Chocolate Sheet Cake with Peanut Butter Frosting

Fudgy, beyond rich chocolate sheet cake topped with the creamiest peanut butter frosting. Feeds a crowd!

chocolate sheet cake topped with peanut butter frosting, drizzle of melted peanut butter, and peanut butter cups in a baking pan

Happiest of Fridays to you!

I saved a good one for today. I figured we can always use more peanut butter and chocolate on the weekend. Especially if that chocolate is rich beyond belief, that peanut butter is in the form of frosting, and that cake is the size of Texas.

And, of course, all those jazzy toppings.

TGIF.

chocolate sheet cake topped with peanut butter frosting, drizzle of melted peanut butter, and peanut butter cups

I’m so excited because I’ve never shared a chocolate sheet cake recipe on my blog before.

I’ve made this chocolate sheet cake a handful of times for various parties and I remember making it for an office party back when I worked in an office. And the entire thing disappeared in about .04 seconds. People flocked to it like it was a pot of shimmering gold under a rainbow.

pouring chocolate mixture into flour mixture in a glass bowl

2 images of thick chocolate cake batter in a glass bowl and whisked eggs and sugars in a glass bowl

Some cake things you’ll need to know:

The first step we’ll do is melt down some butter with water and cocoa powder on the stovetop. This helps dissolve and hydrate the cocoa powder, which typically tends to dry cakes out. This also helps bring out the cocoa’s flavor. When mixed with a cup of butter, we have some seriously delicious chocolate liquid. Instead of water, you can use black coffee (like my favorite chocolate cake!). It’s completely incredible and truly deepens that chocolate flavor.

Then we’ll mix in all with dry ingredients. The usual suspects like flour, baking soda, and salt. Whisk eggs, sugars, and vanilla extract in another bowl. Combine all of these mentioned ingredients together, then whisk in some buttermilk.

chocolate cake batter in a glass bowl with a whisk

All of this chocolate magnificence goes into a half sheet pan.

Since it’s a thin cake, the bake time is quick. Which means it won’t take long to cool, either. Which obviously means that you can cut into this chocolate cake and fall immensely in love sooner. But before all that, let’s frost it with the most unbelievable peanut butter frosting on the planet. It’s my go-to peanut butter frosting recipe, just made larger because this cake is enormous!

spreading peanut butter frosting onto chocolate sheet cake

↑ ↑ Best peanut butter frosting to ever grace this earth.

slice of chocolate sheet cake topped with peanut butter frosting, drizzle of melted peanut butter, and peanut butter cups on a white plate with a fork

One bite = super moist, fudgy, tender, and decadent with a party of texture on top in the form of: peanut butter cups, melted peanut butter, chocolate sprinkles, peanut butter chips, and more.

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chocolate sheet cake topped with peanut butter frosting, drizzle of melted peanut butter, and peanut butter cups

Chocolate Sheet Cake with Creamy Peanut Butter Frosting

  • Author: Sally
  • Prep Time: 30 minutes
  • Cook Time: 20 minutes
  • Total Time: 2 hours, 50 minutes
  • Yield: serves 25-30
  • Category: Cake
  • Method: Baking
  • Cuisine: American

Description

Fudgy, beyond rich chocolate sheet cake topped with the creamiest peanut butter frosting. Feeds a crowd! I encourage you to read the full recipe and the recipe notes before beginning so you’re completely prepared.


Ingredients

  • 1 cup (230g) unsalted butter
  • 1 cup (240ml) water
  • 1/2 cup (41g) unsweetened natural cocoa powder (not dutch-process)
  • 2 cups (250g) all-purpose flour (spoon & leveled)
  • 1 teaspoon baking soda
  • 1/4 teaspoon salt
  • 2 large eggs, at room temperature
  • 1 cup (200g) granulated sugar
  • 1/2 cup (100g) packed light brown sugar
  • 2 teaspoons pure vanilla extract
  • 1/2 cup (120ml) buttermilk, at room temperature*

Peanut Butter Frosting

  • 1 and 1/2 cups (405g) creamy peanut butter (do not use natural style)
  • 1/2 cup (115g) unsalted butter, softened to room temperature
  • 3 cups (360g) confectioners’ sugar
  • 1/2 cup (120ml) heavy cream, half-and-half, or whole milk*
  • 1 teaspoon pure vanilla extract
  • pinch salt
  • toppings: ½ cup (135g) melted creamy peanut butter for drizzling, 1 cup chopped peanut butter cups, handful of mini chocolate chips or peanut butter chips, and/or chocolate sprinkles*

Instructions

  1. Preheat oven to 350°F (177°C). Generously grease a 12×17 inch half sheet/jelly roll pan. Set aside.
  2. Heat the butter, water, and cocoa powder together in a large saucepan over medium heat. Whisk constantly until the butter has melted and everything is smooth and combined. Set aside. In a large bowl, whisk the flour, baking soda, and salt together. Pour the warm chocolate/butter mixture on top, then slowly whisk together until combined. It will be very thick.
  3. Whisk the eggs, granulated sugar, and brown sugar together in a medium bowl. The mixture will be thick. Whisk in the vanilla until combined, then pour into the chocolate batter and whisk until combined. Finally, whisk in the buttermilk. Pour the chocolate batter into the sheet pan.
  4. Bake for 15-20 minutes. (Mine takes exactly 17 minutes.) Use a toothpick to test for doneness: stick it into the cake. If the toothpick comes out clean, the cake is done. If not, continue baking. Remove cake from the oven and set the pan on a wire rack. Allow the cake to cool completely in the pan before frosting. The refrigerator helps speed things up, if you have room for the large pan!
  5. Make the frosting: Using a handheld or stand mixer fitted with a whisk attachment, beat softened butter and peanut butter together on medium-high speed for 2 minutes until completely smooth and creamy. Add the confectioners’ sugar, cream, vanilla extract, and salt. Beat on low speed for about 20 seconds, then gradually increase to high speed. Beat on high for 1 minute until combined and frosting is fluffy. Taste; add more salt if needed. To thicken, add more confectioners’ sugar and to thin, add more cream.
  6. Spread frosting all over cooled cake, then top with toppings. Slice and serve. Cover leftovers tightly and store in the refrigerator for up to 5 days. It’s so good cold!

Notes

  1. Make Ahead & Freezing Instructions: Cake can be made 1 day in advance, covered tightly at room temperature, and then frosted before serving. Frosting can also be made 1 day ahead of time– cover tightly and keep in the refrigerator. Bring frosting to room temperature before spreading. Frosted cake can be frozen up to 2 months; thaw overnight in the refrigerator and bring to room temperature before serving.
  2. Buttermilk: Buttermilk is required for this recipe. You can make your own DIY version of buttermilk if needed. Add 1 teaspoon of white vinegar or lemon juice to a liquid measuring cup. Then add enough whole milk to the same measuring cup until it reaches 1/2 cup. (In a pinch, lower fat or nondairy milks work for this soured milk, but the cake won’t taste as moist or rich.) Stir it around and let sit for 5 minutes. The homemade “buttermilk” will be somewhat curdled and ready to use in the recipe.
  3. Heavy Cream: Using heavy cream, half-and-half, or whole milk in the frosting produces the creamiest texture. (I use and highly recommend heavy cream.) If needed, you can use a lower fat or nondairy milk.
  4. Room Temperature Ingredients: Here is why the ingredients must be at room temperature. The butter is melted and warm, so it’s best the other ingredients are not cold.
  5. Toppings: So many toppings! Use what you like best. I also topped the cake with these Reese’s peanut butter sprinkle ice cream topping (I found it near ice cream aisle)
  6. Sheet Pan: I own and love this 12×17 half sheet pan!
  7. Cake batter adapted from All Recipes.

Keywords: chocolate sheet cake, chocolate cake with peanut butter frosting

Add this to your weekend plans.

chocolate sheet cake topped with peanut butter frosting, drizzle of melted peanut butter, and peanut butter cups

57 Comments

  1. My husband had the worst time at work this week and I knew this would be the perfect thing to brighten up his Friday. I actually half’ed the recipe (it’s just the two of us – enough cake for 30 people in the house would be over-kill!) and cooked it in a regular cake pan and it turned out wonderfully! I was concerned the pan size difference wouldn’t work with the time/temperature, but I had no issues. I couldn’t find any peanut butter chips at the store so I tried butterscotch chips which were good, but would definitely use peanut butter chips next time or make the frosting more peanut buttery. Was a good way to end our week though 🙂

    1. I’m so glad you commented! From the moment I saw this I was thinking ‘Hmm…I wonder if the recipe would work if cut in half?’ because I want to make it, but don’t want to eat 25 portions of cake! Can you tell me what size cake pan you used? 
      Thanks!!
      h

      1. I used a 13″ by 9″ cake pan. Still cooked it at 350°F for ~15 minutes and had no issues at all. 

  2. Made it tonight. Phenomenal!

  3. Hi Sally, What is your opinion on Hershey’s special dark cocoa powder which is a combo of natural and dutch process?    Can I use it in this recipe? (I already have it in my pantry).

    1. You can definitely use it in this recipe, yes. I love it!

  4. I just made this cake and the texture is incredible! The frosting tastes just like your peanut butter fudge, which is definitely the best fudge I’ve ever tried!

  5. Ariane Smith says:

    Hi Sally! I have always been a fan o‎f your recipes. I’ve made a few of them and my family are big fans of such delicious treats! I’m browsing on your cake recipes for our son’s First Communion next month and found this one, I think he would loooove this (PB and chocolate are his favorite thing in the world! Lol) btw, I’m wondering how to make the melted peanut butter for topping? I’ve never done that before and I don’t want to mess anything for the cake.. thank you! 🙂 

    Always your fan,
    Ariane‎

    1. It’s so simple! Use commercial style peanut butter like Jif or Skippy and melt in the microwave for 30ish seconds. Then drizzle on top. Hope everyone loves it!

  6. I made this cake for a bridal shower and everyone raved over it. Even the servers and cooks wanted some, which they could because there was plenty! I was nervous making a cake for a big event, but your recipes ALWAYS come out perfectly, so I was confident. Thank you so much for another wonderful recipe. 

  7. Hi, Sally!  My son has a peanut allergy – any of your icings that you would recommend to use instead that would generate enough icing to cover this gorgeous sheet cake?

    1. This fudge frosting. There will be plenty to use for this cake. Double chocolate! 🙂

  8. This is the first chocolate sheet cake I have ever made and will be the only recipe I’ll ever need! If you’re looking for a super fudgey chocolate cake that everyone will love then there’s no point in searching for any other recipe – this is the one, I promise!!

  9. Could I make this in a bundt pan? 

    1. I can’t see why not!

      1. I made it 2 days ago and I’m currently making it again! Everyone loved it, it’s so fudgy and delicious! Thank you once again Sally for an amazing recipe. 

        P.s: I used the bundt pan and it took 30~35 minutes. 

  10. Hi Sally!
    I’m baking a chocolate cake for my boyfriends birthday and he loves the chocolate peanut butter combo. I wanted to do a layer cake though, would you suggest using your chocolate layer cake recipe and doing this peanut butter frosting or can you make this cake into a layer one? 

    Thanks!

    1. Hi Megan! I would just use the layer cake recipe.

  11. Made this over the weekend for a birthday celebration. It was a huge hit. Thank you, Sally!

  12. Hi Sally! So I want to make this cake as a graduation cake, but the person I am baking for requested their cake be half vanilla, half chocolate. Do you have any suggestions on how I could do that? I thought if I cut this recipe in half, and then your vanilla sheet cake recipe in half, and put them on either side of the sheet pan to bake that might work, but they may run together. The other idea I had was to bake each separately on half sheet pans and then put them together in a sheet pan to frost….what would you suggest? I hope you can help, thanks!

    1. What a great question and you definitely have the right idea! Here’s what I would do– two separate cakes (half sheet pans) then put together and frost. It would be difficult to get a clean line separating the two flavors.

  13. “Good one” is a total understatement. This looks AMAZING! I cannot wait to try this recipe. Always love stopping by!

  14. I just made this frosting for a chocolate cake. It’s a 6 layer cake and let me just let you. THIS FROSTING IS INCREDIBLE!!!! I’m obsessed with it and it reminds me of the center of the Reese’s cup. Absolutely incredible frosting!!!!!

  15. Hi there!! I know this might be a long shot, but I’m wondering about how deep you fill the jelly roll pan. I’m making this cake for about 70 folks tmrw, so I’m baking it in a 21″ x 15″ x 1″ sheet pan. I plan on doubling the recipe, but I think I’ll need a little less the full batter in the pan. Does that make sense?! So to get to my question, about how deep in this 1″ thick pan should the batter be?! About 1/2?! 3/4?! I’ll obviously have to eyeball but I don’t want to have to overflow or be too thin 🙂 

    Thanks for your time, Sally!! I make your Oreo cooking recipe for friends’ bday + they’re always a hit!! 

    1. Hi Kristen! I would fill only halfway.

  16. This frosting is amazing! I used it to top a very large batch of brownies and sprinkled pretzels on top and got rave reviews at our cattle branding. Thanks!

  17. I made this for a large crowd and it was absolutely delicious!!! There was not a crumb left in the pan. I think this was the best chocolate cake I have ever had and the frosting had plenty of wonderful peanut butter flavor!! I will definitely make this cake again!! Made it just as it was in the recipe and it was perfect! Thank you so much!!!

  18. Marlene Cohen says:

    Can I use this peanut butter frosting recipe to pipe on a cake? Will it hold?

    1. Absolutely!

  19. This cake was simply amazing! Very rich so I could cut it into little squares and it was more than enough for everyone at work to enjoy! Thanks!

  20. I needed a quick, easy recipe with pantry ingredients that would feed a crowd. This is it! Thank you so much for a delicious recipe. I made it exactly as directed and it was a huge hit. I will definitely be making this one again!

  21. Hi, Sally. Can this recipe be used to make 8-9 inch round cakes instead of a sheet cake? Thank you. 🙂

    1. Hi Michele! Absolutely. Though I do have a preferred chocolate cake recipe for layers if you want to try that instead.

  22. This is the best chocolate sheet cake E-V-E-R! I made it to use in your petit fours recipe, and it was AMAZING! I had one little square of just plain cake and almost ate the whole thing in one go. This cake is ridiculously good; moist, chocolate-y, soft…yummmmmmm! For someone who loves making fancy layer cakes with all the fuss and frills, I think I could easily choose this simple sheet cake over any layer cake 😀 Honestly, it really is THAT good!

  23. YUMM!! just a word of advice-make sure your frosting ingredients are truly room temp! I added my cream cold and the whole thing kind of seized up- still DELISH and I’m going to use it for buckeye’s, but in order to get that nice whipped frosting DON’T add cold ingredients 😉

  24. This was awesome. I made almost exactly as written with the addition of Reese’s pieces to the topping. Will definitely make it again!!

  25. Hello Sally,
    Can I make this into a layer cake? I’m on Corona lockdown and my ingredients are limited. I’m trying to make a birthday cake for my husband. Please advise. Thankyou!

    1. Hi Freckles, you can but I’m unsure of the exact bake time. I recommend my chocolate cake recipe.

  26. I made this cake twice, once with baking soda as directed and once with baking powder to see if i could get it to rise more. They both came out very flat.

    I tried to roll one of the cakes into a jelly roll to make it look more appealing but it fell apart. This cake turns out more like a bar than a cake.

    I ended up cutting one of the cakes into thirds and using the broken bits of the other cake to layer in between to get some loft.

    The flavor is good and it is very moist, and the frosting is very good. I did use natural peanut butter, I just poured off the oil and only used the more solid part of the jar and used my kitchenaid to whip the frosting. That turned out fantastic.

    To be clear, I didn’t expect a lot of loft with with cake, but it is so flat it looks off. Maybe something was off in my kitchen, but I would not make this cake again.

    1. Hi Rachael, thanks so much for your feedback and trying this recipe– I do not recommend it for a jelly roll cake. It’s a very thin cake as you can see in the photos, so I’m sorry you were disappointed. Thanks again for trying it.

  27. Oh. My. Gosh! I just made this peanut butter frosting; woah mama! It is truly THE best peanut butter frosting I have made and eaten!
    Thank you for sharing! Can’t wait for my family and friends to try it too.

  28. Hi Sally! I have to make a 2 layer 9 x 13 chocolate sheet cake with chocolate buttercream frosting for a party this weekend. Would this recipe work if I divided the batter evenly into two 9 x 13 pans, frost, stack and then frost the entire cake with the chocolate buttercream??

    1. Stephanie @ Sally's Baking Addiction says:

      Hi Brandi, For a 9×13 inch chocolate cake I recommend this chocolate cake recipe and see the recipe notes for instructions on how to bake in that pan. Bake it twice instead of doubling for the best results for 2 layers.

  29. Good afternoon!

    What would you recommend for the cake and frosting recipe If I wanted to use three 6 inch round pans?!

    1. I recommend the batter for my super moist chocolate cupcakes, reviewing my 6 Inch Cakes post for baking instructions/details, then topping with this peanut butter frosting. Enjoy!

  30. My wife says this is the best frosting she has ever tasted.
    I used a box cake mix but made a double batch of the frosting.
    Wow!
    Thank you.
    Roy

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