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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Lori Ford
January 20, 2023This 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!
RobinK
April 29, 2023Love this Peanut Butter Sheetcake!! I use Smooth PB in the cake and Crunchy in the frosting! Yum Yum
Sandra
May 7, 2023Hi, 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,. 🙂
Elizabetb
June 9, 2023I made this the night before I needed it. Should I refrigerate overnight, or is fine left on the counter covered?
Kelly
July 3, 2023I 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.
Wenni
July 14, 2023Making right meow. Just had to add vanilla to batter as well (super old school) trait. Batter was delish, though😬
Brenda
July 12, 2024My cake turned out great but the icing I made was thick. What did I do wrong?
Wendy
February 25, 2024I made this cake and it is all the best parts of peanut butter, love,love,love, how should I store it? Is my question.
Emily
March 14, 2024Do 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?
Rachel Barkowski
March 14, 2024You don’t have to wait for it to cool! 🙂
Kaye
March 18, 2024It was perfect! So moist and delicious. I will definitely be making it again.
Dana
July 6, 2024I made this with the new Jif chocolate peanut butter. It was delicious!