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!!!
Lauren
March 30, 2019Can 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.
Rachel Barkowski
April 1, 2019Yes, you can! 🙂
Mary Meyer
April 8, 2020Can you use butter instead of margarine?
Elisabeth Judy
April 9, 2020Yes, we have made this recipe both ways, with margarine or with butter!
Lilian Ortiz
June 26, 2020how much is stick margarine? how many grams??
Rachel Barkowski
May 4, 2022One stick of butter or margarine is about 113 grams. 🙂
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.
Kim
July 19, 2020I 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
Laura
August 18, 2020I made this and wouldn’t change a thing! Our family devoured it. This will be a staple at our house
Rachel Barkowski
May 4, 2022It is at ours, too! 🙂
Connie
September 6, 2020Not 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
Rachel Barkowski
May 4, 2022It’s just all-purpose flour. If we use self-rising in any of our recipes, we will definitely specify. 🙂 Good luck!
Liz R
September 13, 2020I’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.
Rachel Barkowski
May 4, 2022Just plain white all-purpose flour 🙂
Doug
September 18, 2020Do you put the powdered sugar in while the mixture is boiling or take it off the stove. Mine came out thick
Rachel Barkowski
May 4, 2022As 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.
Patricia
October 7, 2020Will this recipe make enough for a round layer cake
Rachel Barkowski
May 4, 2022Yes it will 🙂
Beth-Ann Smith
October 24, 2020One of our family’s favorite desserts!
Rachel Barkowski
May 4, 2022Yessss!!
Alice Sage
July 9, 2024Should I put cake in fridge! It turned out great!