The Perfect Peanut Butter Sheet Cake
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!!!
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Betty Shanks
March 18, 2021Can you use butter instead of margarine?
Rachel Barkowski
March 22, 2021Absolutely!
Mike
May 13, 2024Mine was on the gummy side as well. I’ll try sifting the flour next time. I used one 9×13 pan and baked it for 45 minutes. The cake was delicious.
Cathy A VanLiew
June 26, 2021Question do I let the peanutbutter sheet cake before applying the hot frosting?
Rachel Barkowski
May 4, 2022Cake doesn’t need to cool first – we pull the cake out of the oven and pour the frosting over it! 🙂
Rhonda
June 28, 2021Hello!
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!
Rachel Barkowski
May 4, 2022Hm, 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.
Rhonda
June 28, 2021Hello!
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!
Lisa
April 19, 2022Try sifting your flour- twice. Then use a spoon to fill the measuring cups so as not to compact the flour.
Rachel Barkowski
May 4, 2022Like Lisa said, it sounds like your flour settled. I shake up my canister first to “fluff” it up instead of sifting…. 🤪
James
July 20, 2021Made this twice, excellent!!!
Rachel Barkowski
May 4, 2022Yay! It’s a family favorite!
Nikki
December 23, 2021This frosting was thick and not useable. Has anyone else had this issue? And what was your remedy?
Rachel Barkowski
May 4, 2022If 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.
Rachel Barkowski
May 4, 2022Also make sure as SOON as it boils, you remove from heat so it doesn’t thicken up.
Joy
July 9, 2022I 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.
Betsy
March 11, 2022You only answer the questions about butter, what about the other questions?
Jan morgan
June 3, 2022Can you use just a 9 by 13 for the entire mixture?
Kathy
August 17, 2022This cake is a keeper! Came out wonderfully and is so moist!
Tammy
October 11, 2022Can 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.