LOOKING FOR A DESSERT TO FEED A CROWD? THIS YUMMY PEANUT BUTTER SHEET CAKE WILL SERVE PLENTY! PERFECT FOR YOUR NEXT SUMMER BBQ, PICNIC, POT LUCK, OR FELLOWSHIP.
THIS DESSERT….. MMMMM.
The cake turns out moist and delicious and peanut buttery. And the frosting! Rich and even more peanut buttery. 🙂 It forms just a slight crustiness, making it simple to serve. No sticking to the plastic wrap or icing falling down the sides of each piece. I like to serve it on napkins and without silverware for a quick and easy end to a meal!
Certainly, a crowd favorite! Just take it to your next get together and you will find out!
Our S’mores Bars are also a crowd favorite!
By the way, if you are looking for a good sheet pan, I highly recommend the one that I have!
This commercial “half-sheet” by Nordic Ware is made from natural aluminum, which means it won’t rust. (I’ve used mine on a regular basis for years and don’t have even one spot of rust on it!)
I spray it with cooking spray and have never had a problem with anything sticking. So if you want a reliable one that will last, I recommend THIS ONE! 
Peanut Butter Sheet Cake
Ingredients
Cake
- 1/2 cup peanut butter
- 1 cup water
- 2 sticks margarine
- 2 cups flour
- 2 cups sugar
- 1 tsp salt
- 1 tsp baking soda
- 2 eggs
- 1/2 cup buttermilk
Frosting
- 1 stick margarine
- 1/2 cup peanut butter
- 6 Tbs buttermilk
- 1 tsp vanilla
- 4 cups powdered sugar
Instructions
- In bowl, mix together flour, sugar, salt and soda.
- In saucepan, mix together peanut butter, water and margarine.
- Bring to a rapid boil and pour over the flour mixture.
- Mix together and add the eggs and buttermilk.
- Pour into greased sheet cake pan. (or 2 - 9x13 pans) Bake at 350° for 20-25 min.
Frosting
- Bring margarine, peanut butter and buttermilk to a rapid boil.
- Remove from heat and add vanilla and powdered sugar.
- Frost cake while the frosting is still hot.
- Let cool completely and cut into bars.
If you’re looking for another dessert to feed a crowd, check out these crazy good S’mores Bars!!!
It was perfect! So moist and delicious. I will definitely be making it again.
Do you wait for the cake to cool completely before you pour the hot frosting on? Or do you pour the hot frosting on while the cake is still hot?
You don’t have to wait for it to cool! 🙂
I made this cake and it is all the best parts of peanut butter, love,love,love, how should I store it? Is my question.
Making right meow. Just had to add vanilla to batter as well (super old school) trait. Batter was delish, though😬
I forgot to add the vanilla into the icing and have already iced my cake. Is this a terrible thing? The icing tastes ok that I’ve scraped out of the pan. I really don’t want to scrap the whole thing if I don’t have to.
I made this the night before I needed it. Should I refrigerate overnight, or is fine left on the counter covered?
Hi, I just came across this page. My Daughter in Law’s Mom makes a peanut butter cake with cooked peanut butter icing but won’t give out the recipe. I would love to try this, But Buttermilk in the Icing ?? Would that make it sour or will it counter the sweetness from the powder sugar ?? Thanks for your time,. 🙂
Love this Peanut Butter Sheetcake!! I use Smooth PB in the cake and Crunchy in the frosting! Yum Yum
This is awesome! I found this recipe a week ago and am ashamed to admit it, but I just made it again!! just made 1/2 of the recipe at a time but there is only two of us! I was afraid the whole recipe would get stale…boy was I wrong!
Can you make this and freeze it. I like to make things ahead of time for Thanksgiving so I am not killing myself the day before.
This cake is a keeper! Came out wonderfully and is so moist!
Can you use just a 9 by 13 for the entire mixture?
You only answer the questions about butter, what about the other questions?
This frosting was thick and not useable. Has anyone else had this issue? And what was your remedy?
If you use the exact frosting ingredients and measurements, it is actually thin when hot – you pour it over the cake while it’s hot and it sets up.
Also make sure as SOON as it boils, you remove from heat so it doesn’t thicken up.
I also had a problem with it being to thick and I also put the icing on while it was still very hot. It still tastes wonderful, but isn’t pretty . Thanks for posting the recipes. I will try adding more buttermilk next time.
Made this twice, excellent!!!
Yay! It’s a family favorite!
Hello!
Is there something I could do to make this cake more “cakey”?
Mine is too gummy? in spite of baking till edges are slightly browned and pulling away. But very delicious!
Thank you!
Try sifting your flour- twice. Then use a spoon to fill the measuring cups so as not to compact the flour.
Like Lisa said, it sounds like your flour settled. I shake up my canister first to “fluff” it up instead of sifting…. 🤪
Hello!
This is a delicious recipe. The frosting is just like you described. Love it.
I was not as happy with the texture of the cake. It is so moist that it it too moist for me. Almost a little gummy. Could give the impression of not being done. I baked it 25 minutes. The edges were slightly browned and starting to pull away from the pan. Is there any advice for making this a bit more “cakey” ? Thank you!
Hm, maybe just a bit more cooking. And it’s possible that your flour settled in the bag or canister, so if you didn’t shake it or sift it first, you may have had more flour than needed.
Question do I let the peanutbutter sheet cake before applying the hot frosting?
Cake doesn’t need to cool first – we pull the cake out of the oven and pour the frosting over it! 🙂
Can you use butter instead of margarine?
Absolutely!
One of our family’s favorite desserts!
Yessss!!
Will this recipe make enough for a round layer cake
Yes it will 🙂
Do you put the powdered sugar in while the mixture is boiling or take it off the stove. Mine came out thick
As soon as it is all melted and reaches boiling, remove it from the heat and stir the powdered sugar in. Boiling for even a couple of minutes will thicken it right up.
I’d like to try your recipe, but I have the same question as the previous person – is the flour used in this recipe all-purpose / plain or self-raising? Many thanks.
Just plain white all-purpose flour 🙂
Not to sound ignorant but I wanted to make this for a family gathering tomorrow, but i don’t bake frequently and the above recipe doesn’t specify all purpose or self rising flour
It’s just all-purpose flour. If we use self-rising in any of our recipes, we will definitely specify. 🙂 Good luck!
I made this and wouldn’t change a thing! Our family devoured it. This will be a staple at our house
It is at ours, too! 🙂
I see the recipe posted with 1/2 milk and using butter. The water on the other recipe is not included. The heat as well is 400 to 350 is the only difference, I LOVE peanut butter my boys as well. Your post I’m just loving so I’m just curious about the buttermilk and the water in the recipe I’m so excited to make for them. Does the Buttermilk give it that added wow to bring out the peanut butter? Any suggestions I’d love you guys are great. Any peanut butter bread maybe? Thanks so very much! God Bless you all
how much is stick margarine? how many grams??
One stick of butter or margarine is about 113 grams. 🙂
Can you use butter instead of margarine?
Yes, we have made this recipe both ways, with margarine or with butter!
Can I halve this recipe and make it in a 9×13? I see that it works for two 9×13’s as is but I’m curious if it will actually be enough batter/frosting.
Yes, you can! 🙂