This Peanut Butter Sheet Cake takes less than an hour to make from start to finish. It’s topped with a fudgy, candied peanut butter icing that’s out-of-this-world amazing! Recipe includes a how-to video.
A Peanut Butter Lover’s Dream Cake
Sure, layer cakes are impressive, but there’s something to be said about classic, from-scratch sheet cakes. Their ease (no leveling, layering, crumb coating), flavor (just as good!), and nostalgic, homey feel is simply unparalleled in the cake world. Today’s tender peanut butter sheet cake is no different; it’s simple, flavorful, and is decorated and served right in its baking dish. It’s a classic!
This cake has a balanced peanut butter flavor that’s prominent without being too overwhelming. My favorite part is the frosting though…it’s like a candied peanut butter fudge topping! It’s super rich (so we use just the right amount) and pairs beautifully with the texture of the cake.
I think you’re really going to love this one, so let’s dive right in!
What You Need
Here are the key ingredients in this peanut butter sheet cake:
- Peanut butter. Do NOT use “natural” peanut butter that separates! Unfortunately, in many peanut butter recipes (like my buckeyes, peanut butter balls, and the frosting on my peanut butter chocolate cake) readers have reported oily failures when they tried to use natural peanut butter, so best bet is to avoid it here. I prefer to use creamy peanut butter, but crunchy could be used instead.
- Butter. I highly recommend using unsalted butter in this recipe (and most of my others!). I have a post comparing salted vs. unsalted butter that you can check out if you’d like an in-depth explanation, but essentially, unsalted butter allows for better precision. This is especially important when using a salted ingredient like peanut butter
- Buttermilk. If you don’t have buttermilk, you can always use my easy buttermilk substitute, but the real stuff will give you the best flavor and moisture.
- Brown sugar. Light brown sugar adds some depth to the cake that really complements the peanut butter flavor well, like in my peanut butter cookies.
- Baking soda. Make sure to use baking soda and not baking powder–they are not the same thing! If you want to learn more about the differences between the two, read my post on baking powder vs. baking soda.
SAM’S TIP: When making your frosting, you’ll want to stir CONSTANTLY once the butter melts. When the mixture comes to a boil, remove it immediately to prevent any burning.
Remember, this is just an overview of the ingredients I used and why. For the full recipe please scroll down to the bottom of the post!
How to Make It
- Whisk together the dry ingredients and sugars in a large bowl and set aside.
- Bring oil, butter, and water to a boil over medium heat.
- Remove the pan from the heat and stir in your peanut butter until it’s melted and smooth.
- Pour your peanut butter mixture into your dry ingredients and mix until combined. Let cool 5-10 minutes.
- Combine buttermilk, eggs, and vanilla, then stir this into your prepared batter until just combined.
- Pour batter into a greased pan and bake for 30-32 minutes.
- Measure and sift your sugar, then set it aside.
- Cook buttermilk, butter, peanut butter, and salt over medium-low heat until the butter melts, then increase heat to medium and whisk constantly.
- Once the mixture boils, remove it from the heat and whisk in the powdered sugar and vanilla.
- Pour the icing over the warm cake and use an offset spatula to smooth.
SAM’S TIP: Once your frosting is fully prepared, you need to work quickly to get it on the cake. The frosting will solidify somewhat, and you want that to happen on the cake–not in the bowl!
Frequently Asked Questions
Nope! Not unless you want it refrigerated, anyway. Simply store at room temperature covered or in an airtight container and enjoy within three days.
Definitely! When I first published this recipe, I used my peanut butter frosting (with some chocolate added to half the batter for a swirl), so that’s always an option. My Texas sheet cake frosting, my chocolate fudge frosting, or just about any other frosting would work well, too.
Yes! You’ll want to wrap it well and store in an airtight container for up to three months.
Baking, decorating, and serving all in the same pan–the beauty of a sheet cake!
Enjoy!
Let’s bake together! I’ll be walking you through all the steps in my written recipe and video below! If you try this recipe, be sure to tag me on Instagram, and you can also find me on YouTube and Facebook
Peanut Butter Sheet Cake
Ingredients
Sheet Cake
- 2 cups (250 g) all-purpose flour
- 1 cup (200 g) granulated sugar
- ¾ cups (150 g) light brown sugar firmly packed
- ¾ teaspoon baking soda
- ¾ teaspoon salt
- 1 cup (237 ml) water
- ¾ cup (177 g) unsalted butter cut into pieces
- ¼ cup (60 g) avocado, canola or vegetable oil
- ½ cup (145 g) creamy peanut butter
- ½ cup (118 ml) buttermilk
- 2 large eggs room temperature preferred
- 1 ½ teaspoons vanilla extract
Fudgy Peanut Butter Frosting
- 4 cups (500 g) powdered sugar
- ½ cup (118 ml) buttermilk
- 10 Tablespoons (150 g) unsalted butter cut into pieces
- ⅔ cup (165 g) creamy peanut butter
- ¼ heaping teaspoon salt
- 1 teaspoon vanilla extract
Recommended Equipment
Instructions
- Preheat oven to 350F (175C) and lightly grease a 13×9 baking pan. Set aside.
- In a large bowl, whisk together flour, sugars, baking soda, and salt.2 cups (250 g) all-purpose flour, 1 cup (200 g) granulated sugar, ¾ cups (150 g) light brown sugar, ¾ teaspoon baking soda, ¾ teaspoon salt
- In a medium-sized saucepan, combine water, butter, and oil. Heat over medium heat, stirring occasionally until butter is melted and bring to a boil.1 cup (237 ml) water, ¾ cup (177 g) unsalted butter, ¼ cup (60 g) avocado, canola or vegetable oil
- Once boiling, remove from heat and add peanut butter. Stir until peanut butter is dissolved and mixture is smooth. Add to bowl with dry ingredients and stir until combined. Set aside to cool for 5-10 minutes.½ cup (145 g) creamy peanut butter
- Meanwhile, in a separate bowl, whisk together buttermilk, eggs, and vanilla extract.½ cup (118 ml) buttermilk, 2 large eggs, 1 ½ teaspoons vanilla extract
- Gradually stir buttermilk mixture into batter, stirring until just combined.
- Pour batter evenly into prepared pan and transfer to center rack of 350F (175C) preheated oven and bake for 30-32 minutes or until a toothpick inserted in the center comes out clean or with moist crumbs. Prepare frosting.
Fudgy Peanut Butter Frosting
- Measure out sugar and set aside (if you’re worried about lumps in your icing, sift the sugar after measuring).4 cups (500 g) powdered sugar
- Combine buttermilk, butter, peanut butter, and salt in a medium-sized saucepan. Cook over medium-low heat until butter is melted. Increase heat to medium and bring to a boil while stirring constantly. Once boiling, remove from heat.½ cup (118 ml) buttermilk, 10 Tablespoons (150 g) unsalted butter, ⅔ cup (165 g) creamy peanut butter, ¼ heaping teaspoon salt
- Immediately add powdered sugar and vanilla extract.1 teaspoon vanilla extract
- Whisk until smooth and immediately pour evenly over cake (in the pan, I do not remove my cake from the pan).
Notes
Jelly Roll Pan
To bake in a jellyroll pan (15×10″ pan) bake on 350F for 18-22 minutes.Peanut Butter
I recommend against using a “natural” variety of peanut butter (the kind where the oil separates out) as this could affect the texture of the cake.Creamy or crunchy peanut butter will work here, I prefer creamy for smoother results, but if you opt for crunchy you’ll just have small peanut pieces in your cake and icing.
Storing
Cover the pan with foil or plastic wrap and store at room temperature for up to three days.Nutrition
Nutritional information is based on third-party calculations and should be considered an estimate only. Actual nutritional content will vary based upon brands used, measuring methods, cooking method, portion sizes, and more.
Janice Banks
This is one of the best sheet cakes I have made. It is so moist and delicious. We had a lot of peanut butter left over from hurrican supplies. I wanted to use up the peanut butter because I knew it would go bad. I loved the way your instructions listed the ingredients under each step! This was a great recipe. I will definitely make it again! One of the best things also was, I didn’t have to get put my heavy mixer! Thanks for the recipe.
Sam
You’re welcome, Janice! I’m so glad everyone enjoyed the cake so much! 🙂
Kimberly
This is an amazing recipe and so easy to follow!! I love your style of adding the ingredients needed under each step, keeps me from having to scroll back up to double-check myself (lol!) Always a crowd-pleaser when I make it, I’ve had to share the recipe link MANY times.
Emily @ Sugar Spun Run
We’re so happy you enjoyed it, Kimberly! Thanks for the review 🩷
Courtney
Thank you for this peanut butter cake recipe! My daughter wanted a “Reese’s cake” for her birthday. I followed this recipe and added Reese’s minis (& sprinkles!) to the top. She loved it and so did the rest of our family! Because of allergies, we needed to make it egg-free. I subbed the 2 eggs for ½ cup of club soda (¼ c. for each egg) and it turned out great. I cooked it longer than the recipe called for, for around 40 minutes. It probably took longer because I used a glass pan. One more note – when cooking the ingredients in the saucepan for the icing, it was looking really weird and separated and clumpy. I thought I may have ruined it, but I poured the hot mixture into the powdered sugar then used an electric hand mixer to blend it and it turned out just perfectly and looked like yours. Yay!
Sam
I’m so glad you enjoyed it so much, Courtney! 🙂
Emily C
HOLY CRAP. I made this cake for a potluck this week and everyone went CRAZY for it (myself in included, I had 3 pieces). I made the recipe as directed but also heated up a container of store bought chocolate frosting to swirl in the peanut butter frosting after pouring both on the warm cake. It was a heavenly Reece’s dream. I will DEFINITELY be making this again.
Emily @ Sugar Spun Run
Sounds like it was a huge hit, Emily! We are so happy you came back to leave a review ❤️
Arthur Picot
This recipe sounds really good! I have been looking for a recipe for a peanut butter layer cake and wanted to know what changes, if any would be needed to do that with this recipe.
Sam
Hi Arthur! I haven’t personally tried making it a layer cake, but I have had others report doing so with success. You would just need to alter bake times for the pans you put it in. 🙂
Jill Ellis
Can I use this cake for cake pops?
Sam
Hi Jill! I haven’t tried it, but I think it could work. 🙂
Willie P Wynn
I just made this today and oh my goodness it’s absolutely delicious. The frosting is just heavenly and the cake is so moist. The easiest homemade cake I ever made so easy. I will definitely be making this again. 😋
Sam
I’m so glad you enjoyed it so much, Willie! 🙂
Linda Wobbe
Just like everyone else I have to let you know how much we loved this cake and frosting! The sheet cake made it easier to get a smaller and more convenient portion size. I’d like you to know that we used natural peanut butter with no problems. You do need to stir it up before using.
Sam
I’m so glad you enjoyed it so much, Linda! Thank you for the feedback using natural peanut butter. 🙂
Esther
Would it be possible to try this low carb, as in using almond flour and alternate sweeteners? Ty xx
Sam
Hi Esther! I haven’t tried it so I can’t say for sure how it would turn out. Let me know how it goes if you try it. 🙂
Rose Shickle
Do you add the frosting while the cake is still hot?
Sam
Hi Rose! You will want your cake to be cooled a bit so it doesn’t melt the frosting. 🙂
Shayne
oops…I made this cake a bit ago and assumed we were to pour the frosting right away (as in pouring it right away regardless lol. well I will know in a bit when I check it out lol
Michelle
Have you made this as a free standing cake instead of a sheet cake? I wanted to make this recipe but with the cake freestanding on a cake stand but not sure if it’s a sheet cake on purpose due to the cake possibly falling apart taking it out of the pan. Help 😁
Sam
Hi Michelle! I haven’t, but a few readers in my Facebook group have successfully made the cake as a 2-layer cake rather than a sheet cake. I’m not sure of the exact bake time, unfortunately.
JENNIFER JONES
absolutely delicious cake and frosting. I’ve always had a problem making frosting but this turned out really well!!
Sam
I’m so happy to hear this, Jennifer! Thank you so much for trying my recipe, and for your feedback, I really appreciate it!
Jacque Emanuel
Hi, I just made this cake a few days ago and it is absolutely delicious! I never leave reviews but I just had to comment on this one because the cake is so so good!
Thanks for sharing and have a wonderful holiday!
Sam
I’m so glad you enjoyed it so much, Jacque! 🙂
Tara
This cake was superb!!! The icing is to die for. I even used a gluten free four and it was perfection (Robin Hood GF all purpose flour).
Sam
I’m so glad you enjoyed it so much, Tara! Thank you for the feedback using gluten free flour. 🙂
Liane
This recipe is amazing, probably the best one I have tried! Also, I just wanted to point out that the formatting you use as you give the instructions, listing the ingredients and their amounts needed, as you are explaining the recipe steps it’s genius! I can’t tell you how much that is appreciated! It is frustrating scrolling up and down and up and down! You made it perfectly easy! Thank you for this recipe and the hundreds of others I have made of yours, never had one I didn’t like!!!
Sam
I’m so glad you enjoyed it so much, Liane! Thank you for your feedback. 🙂
Angie
This cake is delicious. I made it for Thanksgiving!! Yum yum. We love peanut butter anything!
Julie Gomez
OMG…. I just made this, and it was AMAZING!!!! The icing is to die for, and I cannot wait to make it again! THANK YOU for sharing your recipe.
Sam
I’m so glad you enjoyed it so much, Julie! 🙂
Carmen
Is this cake sturdy enough to make into a layer cake?
Sam
Hi Carmen! Other people have done so with success. 🙂