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 (42g) 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

149 Comments

  1. Definitely the way to start my Friday. Man, I want some for breakfast. Where you at? Can I swing by? 😉
    I love sheet cakes. They have the perfect frosting/cake ratio!

  2. Vivian | stayaliveandcooking says:

    Those pictures are to die for! Recipe sounds so good, I should not scroll bloglovin with an empty stomach. In desperate need for some chocolate now, and peanutbutter. Saved this one to my “to-bake” list!

  3. Marina @ A Dancer's Live-It says:

    WOW! I think you outdid yourself on this recipe! Happy Friday indeed!! <3

  4. Wow, what great photographs…the one right before the recipe is especially good, in my opinion 🙂 And TGIF indeed! I hope you have a wonderful weekend!

    1. Thanks Caley! Hope you’re weekend’s fabulous 🙂

  5. Cheese and Chinese says:

    I could totally go for a big slice right now! This looks so rich and delicious! 

  6. Oh my gosh, Sally!! This cake looks to DIE for. I honestly don’t even know if I’d be able to share it!

  7. Love this cake. Chocolate and PB is ALWAYS a good idea! 

  8. Okay so, as soon as I saw this, I knew I had to make it cause I was literally drooling all over the computer and what better excuse is there than that?!?! 
    And OH MY GOSH I think this is the best decision I ever made in my life!
    The cake so rich and decadent and the peanut butter frosting is so creamy and peanut buttery!
    The two best flavors ever!
    I couldn’t stop sticking my finger in the bowl of frosting:)
    I think I will need a lot of self control not to make this every week.
    I’m serious
    Oh my pant size!
    And my taste buds!
    Which will win?
    Sally, seriously, why did you do this?!?!
    But, I’m actually really glad you did.
    I love it!

    1. WOW! You already made it? So happy you love it, Kayla! You’re my soul sister because it’s clear you love peanut butter and chocolate as much as I do. Ha! 🙂

  9. Andrea @ Cooking with a Wallflower says:

    That drizzle and all that chopped up peanut butter cups. It sounds soooo delish! And who can ever pass up chocolate cake, right?

  10. Sally! This looks amazing…Chocolate Sheet Cake is one of my faves….but with this peanut butter frosting-OMG! My dad’s birthday is this weekend and he requested some kind of peanut butter chocolate cake. I think this will be perfect!

    1. Hope you all enjoy! Have fun baking!

  11. OMG I’ve made your triple chocolate cake but always used a peanut butter frosting and crumbled reese’s peanut butter cups on top for the last two years, I swear we are on the same wave long, never thought about drizzling peanut butter on top though! My kids and I agree that your cakes are so good on their own that they don’t even need icing, but of course we put it on anyways 🙂 Your cake recipes are the only one’s I ever use, I love how you work so hard on them to get them just right, I completely trust your recipes! Enjoy your weekend Sally!

    1. Brenda, we’re always on the same page! I’m so happy you and your family love my cake recipes! Add this to the list. 🙂

  12. Catherine Smith says:

    You could make a coffee table book from your photography!! I just imagine you have a whole house full of framed photos from your cooking! 🙂 This looks amazing!

    1. I actually don’t have any of my food photography printed out! I never really thought about doing that! You’re so sweet, thank you for the compliment.

  13. My birthday is next sunday, guess what I am baking?!?!?!?! There is no better combination in the world than chocolate and peanut butter (unless you add pretzels:-)

    1. Ohhhhh my gosh. This with crushed pretzels on top!!! You must try it.

  14. Michelle @ Modern Acupuncture says:

    Peanut butter frosting rocks my world. Can’t wait to try this!!! 

  15. I was trying to decide what to make for dessert tomorrow because our son, daughter-in-law and grand kids are here for the weekend and bingo this recipe is the first thing that I look at!! Can’t wait to serve this!!!! Thank you for another winning recipe!!!!

    1. Perfect recipe for company, Wendy! Have a wonderful weekend with your family.

  16. My problem is I have too many sweets to try!!! Stop posting awesome things :3

  17. demeter | beaming baker says:

    Happy Friday, Sally! 🙂 And what a happy weekend it’ll be with this chocolate PB decadence. I seriously cannot believe this is the first sheet cake on your blog! Wow, three years, 5 or so shimmering pots full of gold/chocolate sheet cake later… and you’re the coolest, nicest food blogger on the interwebs. Congrats, Sally. <3

    Of course, I'll have to use coffee in the chocolate step bc… CHOCOLATE + PEANUT BUTTER + COFFEE = All the Good Things in the World Together. Now all I have to do is find excuses to put your PB frosting on everything! Thanks for another great recipe, Sally. Have a wonderful weekend! 🙂

    1. Well, this is the first CHOCOLATE sheet cake on my blog. I have a funfetti version on here too! Have a great weekend Demeter!

      1. demeter | beaming baker says:

        How did I miss that?! I’m such a dork! Now I’m gonna have to go drool over the funfetti version. Thanks Sally! 🙂

  18. Drooling! Pinned this to my peanut butter board 🙂

  19. I am SOOOOOOOO wanting your next cookbook to be CAKES !!!

    Fingers crossed !

  20. I saw this recipe title on my email and my eyes went wide. What a way to celebrate Friday! There really is no better combination than peanut butter & chocolate. I’ll be making this at some point. I don’t know when, but I have to 🙂 

  21. This is soo dreamy!

    Kisses from http://poshnessary.com ❤

  22. Oh boo. Boything is away all weekend for a bachelor party, so I stuffed my weekend full of plans so I won’t miss him too much. I cannot WAIT to make this, though!

  23. Marla Meridith says:

    Looks delicious! Have a wonderful weekend 🙂

  24. Your killing me right now. Oh my goodness. My husband is going to love you even more. I will be making this very soon. Got to go to the store. He loves these two things together. I am bowing down to you. Diet screw any diet. Yeah baby!

    1. Hope you BOTH enjoy!!

  25. Hi Sally

    Could I use Cake flour here for the super soft texture?
     If so, how much quantity instead of the 2 cups?
    Thanks!

    1. I don’t recommend it- the cake would be way too light. Not something you want for a chocolate cake that’s already quite thin as is.

  26. Lynn @ Fresh April Flours says:

    So funny, I was editing pictures for my Texas sheet cake recipe last night! We were totally on the same wavelength. We will miss you tomorrow, but can’t wait for girls’ night next week! Enjoy your weekend, Sally 🙂

    1. Can’t wait for next week!

  27. Sharon K (The Farm Chick Bakes) says:

    Sally!!!! These pictures are scrumptious looking. I MUST make this for my work and take it in on Monday! The only thing bigger than my Salt & Caramel addiction is my Peanut Butter/Choc addiction (thus my #1 candy request…my double sized Choc/Peanut Butter Cups!). Lord have mercy on my waist this weekend as I indulge in all these calories. Thank you Sally, I think! Have a great weekend! Weather’s going to be gorgeous here in PA!

  28. Wow, that looks awesome! And I’m pretty sure I’ll be putting peanut butter frosting on everything from now on…

  29. There’s a joke in our bakery about our peanut butter frosting and myself. It’s the most serious relationship I’ve been in my whole life. The bucket is often labeled, “Lauren’s Bae” or “Lauren’s Creamy Gold”. Lol

    They also leave PB in the jar for me (we are talking like 1/4-1/2 cup haha) to make OIAJ. Love them!

    1. HAHAHA I love it.

  30. 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. So glad you made it! And not at all surprised you loved it. Best cake!

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