Peanut butter sheet cake is the answer for anyone who craves peanut butter but never finds a dessert that truly delivers it. This one bakes up tender and rich, gets a velvety peanut butter frosting, and finishes with crunchy peanuts and shaved chocolate on top.
Why This Peanut Butter Sheet Cake Is a Keeper
- Three layers of peanut butter flavor in cake, frosting, and topping
- Bakes in a single sheet pan for an easy crowd dessert
- Frosting goes on warm and smooths out like a dream
- Spanish peanuts and shaved chocolate add crunch and contrast
It starts a lot like a Texas sheet cake, with butter and water melted together on the stove, only here peanut butter joins the pot. Chocolate and peanut butter are a classic pair, so a scatter of shaved chocolate on top just makes sense.
Frost the cake while it is still slightly warm so the peanut butter frosting spreads into a glossy, even layer.
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Why You’ll Love This Peanut Butter Sheet Cake
- This peanut butter sheet cake is moist and tender without being heavy
- The frosting is fluffy, sweet, and packed with peanut butter flavor
- Spanish peanuts and chocolate give every square a satisfying crunch
Ingredient Notes
Below are notes on the main ingredients and why they matter. The full exact measurements in the recipe card are waiting at the end of the post.
- Peanut butter: used in both the cake and the frosting; a creamy no-stir style blends most smoothly
- Butter: melted with water and peanut butter to start the batter and keep the crumb tender
- Flour and sugar: the structure and sweetness for the cake base
- Confectioners sugar: dissolves into the frosting for a silky, lump-free finish
- Spanish peanuts: their thin red skins and salty bite top the cake beautifully
- Shaved chocolate: run a peeler along a chocolate bar for pretty curls
For equipment, a jelly roll or half sheet pan is the key tool here. A large pot for melting the base and a stand or hand mixer for the frosting round out the list.
How to Make Peanut Butter Sheet Cake
This peanut butter sheet cake comes together on the stovetop and the oven, with no creaming step to fuss over. Here is the friendly overview before the recipe card.
- Preheat the oven to 350 degrees and grease a jelly roll pan
- Melt the butter, water, and peanut butter together in a large pot, then lower the heat
- Stir in the rest of the cake ingredients until just combined and pour into the pan
- Bake for 20 minutes, then remove and let the cake cool
- Beat the frosting ingredients until fluffy and spread over the cooled cake
- Finish with Spanish peanuts and shaved chocolate
One sheet pan yields about 16 squares, plenty for a party or a potluck. You can bake the cake a day ahead and frost it the morning you plan to serve, keeping it covered at room temperature.
Storage Options
This peanut butter dessert stays moist for days thanks to all that butter and peanut butter. Store it however suits your schedule.
- Keep covered at room temperature for up to 3 days
- Refrigerate in an airtight container for up to 1 week
- Freeze unfrosted cake, well wrapped, for up to 2 months
Variations & Substitutions
The peanut butter cake base takes well to small tweaks if you want to change things up. Try one of these ideas:
- Drizzle melted chocolate over the frosting instead of shaving it
- Use chopped salted pretzels in place of peanuts for extra crunch
- Swap honey-roasted peanuts for a touch of sweetness on top
- Add a pinch more salt to the frosting if you like a salty-sweet edge
What to Serve with Peanut Butter Sheet Cake
A square of peanut butter sheet cake is rich, so cool and simple sides pair best. Here is what I like alongside it.
- A tall glass of cold milk, the classic match
- Strong black coffee to balance the sweetness
- A scoop of vanilla ice cream for a warm square
- More peanut butter treats, like this peanut butter chocolate chip pound cake
Here are the questions that come up most when readers bake this cake. If you love nutty cakes, you may also enjoy this cookie butter bundt cake with ganache.
Frequently Asked Questions
Can I make peanut butter sheet cake ahead of time?
Yes. Bake the cake a day early and store it covered, then frost and top it the day you serve for the freshest texture.
What kind of peanut butter works best?
A creamy, no-stir peanut butter blends in most smoothly for both the cake and the frosting. Natural styles can separate.
My frosting is too thick to spread. What do I do?
Beat in a little more milk, a teaspoon at a time, until it loosens. Spreading it on a slightly warm cake also helps.
Can I use a 9×13 pan instead?
You can, but the cake will be thicker and need a few extra minutes in the oven. Watch the center for doneness.
If that peanut butter craving has been following you around, this cake finally puts it to rest. Bake it once and it just might become your go-to dessert for every gathering.
Triple Peanut Butter Sheet Cake
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Ingredients
- 1 cup butter
- 1 cup water
- 1 cup peanut butter
- 2 cups flour
- 1¼ cup sugar
- 1 tsp baking soda
- ⅛ tsp salt
- 2 eggs
- 1 tsp vanilla
- 3 cups confectioners sugar
- 1 cup peanut butter
- ½ cup milk
- Spanish peanuts see notes
- Shaved chocolate see notes
Instructions
- Preheat oven to 350º. Grease a jelly roll or half sheet pan.
- In a large pot over medium heat combine butter, water and peanut butter. Stir until it all melts together. Reduce heat to low. Add the rest of the cake ingredients. Mix until combined. Pour into greased jelly roll pan.
- Bake at 350º for 20 minutes. Remove from oven and cool.
- Combine frosting ingredients in a stand mixer (or use hand mixer) and beat until fluffy.
- Smooth frosting over cooled cake.
- Top with Spanish peanuts and shaved chocolate.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Amen!! Oh my, this looks and sounds absolutely marvelous!! My biggest weakness is M&M Peanuts but this is like those individual delights on sheet cake, velvety frosting, Spanish peanut and chocolate steroids!! I can’t wait to try this recipe Melanie!!
Thank you! It is quite over the top. But some of the best things to eat are over the top.
OMG my husband would LOVE this! I might have to attempt it!!
Karen-
This recipe is so easy. Honestly, the cake and frosting are a cinch. And if you skip the grated chocolate on top and use chocolate chips instead, then it’s even easier!
You are a genius. Would it be overkill to lace the cake with chocolate chips? I think I COULD kill someone ….
Yes! I shaved the chocolate so it would look pretty. Chocolate chips would be perfect and faster!
This looks sooo good. Peanut better is one thing I can eat everyday and never get tired of it. I’ll be trying this very soon.
Thanks Sylvie! Let me know what you think if you make it.
“Frick and frack of the food world”, LOVE it! You are too funny! This is a serious dessert, can’t wait to try it!
You are so right! This is a serious dessert. Have a glass of milk at the ready!
These look DIVINE and I bet addictive too!
It is yummy, but it is rich which makes you stop eating after awhile, lol.
Hello Heaven! mmm looks really good and I love the photos of it!
Thanks Angie! I too love the photos. There’s something about the peanuts that makes it pop a bit.
That looks incredible! I just love pb cake!
Thank you Laura!
Oh how delicious! It would also be awesome with chocolate frosting, then sprinkled with Spanish peanuts. I agree, chocolate and peanut butter is the BEST!
Yes! Chocolate frosting would be fab on this as well. I can just picture a swirly chocolate ganache. Yum!
This uber peanut-y cake would make by dad so crazy happy. He loves munching on peanuts. How many slices did you have? Can’t imagine you finishing this though, cravings do make one’s appetite go wonky. I made microwave mug brownies 2 nights in a row to get my chocolate cravings in check. I’ve become one of those people. LOL.
I’d blush to tell you how many slices I had, lol. And I think we are “one of those people” together.
Can you tell me the approx dimensions of the cake pan/jelly roll that you used?
Wondering if I can half the recipe on a smaller pan…
Good question. 13x8x1