This shortcut recipe for Peanut Butter Sheet Cake starts with a cake mix and tastes like a moist peanut butter brownie, topped with Peanut Butter Frosting and chopped peanuts. The easy icing is made in the microwave and has a fudgy texture without all the work!
No electric mixer required!
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Thank you to my friends at Alabama Peanut Producers Association for sponsoring this recipe.
This peanut butter cake recipe reminds me of a flavorful school cafeteria peanut butter sheet cake that you'd get for dessert once a week. For peanut butter lovers, it's the ultimate treat!
You may also hear this peanut butter cake called Texas Peanut Butter Sheet Cake. That's because it's similar to a chocolate Texas sheet cake with a poured icing but made with peanut butter and peanuts. But, this one has no buttermilk!
You may also love my White Texas Sheet Cake and Texas Sheet Cake Cookie recipes. Both are also made with cake mix!
I have made this cake at least 6 times already and every time I take it somewhere, I return with an empty pan and rave reviews! Perfect for potluck crowds, Thanksgiving, Christmas or just because you want CAKE!
It's truly a peanut and peanut butter-lovers dream dessert!
Shortcuts
- No mixer needed.
- Starts with a cake mix, so less measuring.
- Using a 16 ounce box of powdered sugar not only ensures the correct amount to use but saves time measuring 3 ¾ cups sugar.
- Melt butter and peanut butter in the microwave!
🥜Fun Fact: One ounce of peanuts has 7 grams of protein!
Ingredients
What you will need to make this easy peanut butter cake recipe.
Scroll down to printable recipe for exact ingredient quantities.
- Cake Mix - Yellow or Golden Butter cake mix. I used Duncan Hines.
- Milk - Whole milk, skim milk, 2 percent milk, etc. Even water can be used in the cake but milk makes it more tender. No buttermilk needed.
- Peanuts - To sprinkle on top of the cake. I like cocktail peanuts but you can also use Spanish peanuts or dry roasted peanuts.
How to make this easy Peanut Butter Sheet Cake
Scroll down to the bottom for the printable recipe with detailed instructions.
- Preheat oven according to the instructions below. Lightly grease a 15x10-inch sheet pan or 13x9-inch baking pan. (I give baking times for both.)
- Combine butter, peanut butter, and milk in a large microwave-safe bowl. Microwave on HIGH (1100 watts), uncovered, for 1 minute. Stir together until the butter is melted and peanut butter mixture is smooth. Stir in oil and vanilla.
- Add eggs and lightly beat with a spoon or whisk in the center of the batter, then incorporate them into the rest of the batter by stirring well.
- Add the cake mix and stir vigorously with a spoon until no cake mix lumps are visible, about 45 strokes.
- Spoon the peanut butter batter in the prepared baking pan, then spread the batter to the edges of the pan. Bake according to the instructions below depending on what size of pan you used.
- Peanut Butter Frosting: Combine butter, peanut butter, and milk in a large microwave-safe bowl. Microwave on HIGH (1100 watts), uncovered, for 50 seconds. Stir together until the butter is melted. Stir in vanilla and powdered sugar. Stir well until smooth.
- Frosting should be pourable but thick enough to spread.
- When cake has cooled 15 minutes, spread the frosting (icing) over the cake and spread to the edges of the pan.
- Sprinkle with chopped peanuts before the frosting sets.
I also give you directions in the post further down if you don't have a microwave.
Tip: If you prepare the frosting ahead of time and it has become too firm to pour, simply microwave it for 20 to 30 seconds and stir. It will loosen up quickly.
Pro Tips
Don’t scoop the measuring cup into the powdered sugar when measuring. Lightly stir powdered sugar, then spoon it into the dry measuring cup piled up over the top. Use a knife to level off the excess.
Sometimes a box of powdered sugar will have lumps in it. Simply dump the box into a fine mesh sieve or a sifter and shake over the bowl you're going to make the frosting in.
For the frosting, if you are measuring your own powdered sugar from a larger bag instead of using the pre-measured 16 ounce box, reserve 1 tablespoon of the milk. Add the last tablespoon a little at a time to make sure it is spreading consistency without being too thin.
Substitutions & Variations
Trade "this" for "that" in this Peanut butter Cake with Peanut Butter Frosting recipe.
- Milk: Any milk or even water can be substituted for cows milk but dairy milk makes it slightly more tender.
- Peanut Butter: Crunchy peanut butter can be substituted in the frosting instead of sprinkling with chopped peanuts.
- Cake Mix: I've made this with a couple of brands of yellow cake mix and Duncan Hines' Golden Butter cake mix.
How to make Peanut Butter Frosting in a Saucepan.
Combine same amounts of butter, peanut butter, and milk in a large saucepan. Heat over medium heat, stirring often, until melted and smooth.
Remove from heat. Stir in vanilla and powdered sugar. Stir well until smooth.
Frosting should be almost pourable but thick enough to spread. Spread the peanut butter frosting over the slightly warm cake.
How to adjust a recipe for smaller cake mix size
If using the new, reduced-size cake mix (2024+) which are only 13.75 ounces, add ¼ cup all purpose flour. Self rising flour will also work since it’s such a small amount. Use what you have.
I was still able to find the 15.25 ounce boxes of cake mix at my local grocery store and even at the Dollar Tree long after the grocery stores started selling the smaller cake mix size. I'm not sure when they will completely switch over and eliminate the larger cake mix.
Helpful Information
If you have a scale, it is more accurate to weigh 16 ounces than to measure because it’s easy to over or under measure powdered sugar. Use only dry measuring cups and level off the top after lightly spooning it into the cups.
To melt butter and peanut butter in a small saucepan on the stove, combine the butter and peanut butter and cook over medium heat, stirring often, until melted.
What to serve with this easy peanut butter cake
- You can enjoy the moist peanut butter sheet cake with your favorite coffee, warm drinks or a cold glass of milk. It's a delicious combination!
- Pair the cake with your favorite ice cream for a simple birthday party or as a snack cake after school or work.
How to store this peanut butter cake
- To Store: Store, covered, at room temperature or in the fridge. It also freezes well.
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Peanut Butter Sheet Cake with Peanut Butter Frosting
SAVE THIS RECIPE
I'll email this recipe to you, so you can come back to it later!
Ingredients
- ½ cup salted butter, cut into 4 pieces 1 stick
- ⅔ cup creamy peanut butter
- ⅓ cup milk From whole to skim
- ⅓ cup vegetable oil
- 1 teaspoon vanilla extract
- 2 large eggs
- 1 box yellow cake mix or Golden Butter I used Duncan Hines
- ⅓ cup chopped peanuts to sprinkle on frosting
Peanut Butter Frosting
- ½ cup salted butter, cut into 4 pieces
- ½ cup creamy or crunchy peanut butter
- ⅓ cup milk From whole to skim
- 1 teaspoon vanilla extract
- 1 16 ounce box powdered sugar (3 ¾ cups)
Instructions
- Preheat oven to 350F degrees. Lightly grease a 15x10-inch sheet pan or 13x9-inch baking pan. Baking times included for both below.
- Combine butter, peanut butter, and milk in a large microwave-safe bowl. Microwave on HIGH (1100 watts), uncovered, for 1 minute. Stir together until the butter is melted and peanut butter mixture is smooth. Stir in oil and vanilla.
- Add eggs and lightly beat with a spoon or whisk in the center of the batter. Then, incorporate them into the rest of the batter by stirring well.
- Add the cake mix and stir vigorously with a spoon or whisk until no cake mix lumps are visible, about 45 strokes.
- Spoon the peanut butter batter in the prepared baking pan, then spread the batter to the edges of the pan.
- To bake in a 15x10 inch sheet pan, bake for 13 to 15 minutes or until a toothpick inserted in the center almost comes out clean. Do not over bake.
- To bake in a 13x9 inch baking pan, bake for 19 to 21 minutes or until a toothpick inserted in the center almost comes out clean.
- Once done, let it cool in pan 15 minutes before spreading the frosting over it and sprinkling with peanuts.
- For the best slicing, let stand at room temperature one hour before cutting for icing to set up. Or, refrigerate for 30 minutes to get nice clean slices.
Prepare Peanut Butter Frosting (Icing)
- Combine butter, peanut butter, and milk in a large microwave-safe bowl. Microwave on HIGH (1100 watts), uncovered, for 50 seconds. Stir together until the butter is melted.
- Stir in vanilla and powdered sugar. Stir well until smooth. Frosting should be pourable but thick enough to spread.
- When cake has cooled 15 minutes, pour the frosting (icing) over the cake and spread to the edges of the pan.
- Sprinkle with chopped peanuts.
Notes
Nutrition
Nutrition analysis on GritsAndGouda.com recipes are mostly calculated on an online nutrition calculator. I am not a dietitian and nutritional information is an estimate and can vary based on products used.
Kathy
Can you make this in a Bundt pan?
Kathleen
I have not tested it in a Bundt pan but that would be delicious. The baking time would be much more but I think it could absolutely be done! Let me know if you test it in a Bundt pan. I could add that as a reader note in the post!
Jaune
I just put the batter in the oven, and batter is a very loose term. It’s almost like peanut butter Play-Doh. Much more moist than that, but that’s what it reminded me of. Like if I were going to make peanut butter balls. Is that right? It smells delicious and I have high hopes, but I’m a little nervous about it.
Kathleen
It is definitely a "batter". Double check to make sure you added the oil, milk and that the butter was melted.
Jennifer Morgan
I'm going to make the cake now but I want to know if I can use margarine instead of butter
Kathleen
I’m so glad you want to make this cake! While I highly recommend real butter, margarine can probably be used with similar but not exact results.
LErvin
So delicious and easy to make! My peanut butter lovers (kids) really enjoyed it! Thanks for sharing 😊
Kathleen
It has already become a family favorite with my family, too! So glad you're family loved it!
judy smith
My grand daughters love peanut butter. Can't wait to make this for them !
Kathleen
It is truly a peanut butter lovers dream dessert! I hope your granddaughters love it as much as my family does!