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From scratch moist and peanut buttery PEANUT BUTTER CAKE! Pair this 9×13 inch peanut butter cake with chocolate frosting!

slice of peanut butter cake with chocolate frosting on metal plate
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There is one thing I can’t stop thinking about… those tiny delicious Reese’s peanut butter cup eggs that you see in the stores around this time!

Ryan LOVES them, as in he could eat 2 packs in one day… so they are kind of “off limits” in our house.

So I’ve taken to walking by them slowly when I’m at the grocery store, thinking about how peanut buttery they are. And then thinking about how thirsty they make you!! Right?!

slice of peanut butter cake with chocolate frosting on metal plate

I channeled all that peanut butter goodness into this recipe for peanut butter sheet cake! It’s moist, quite peanut butter-y and makes you want to drink a glass of milk :)

You make this sheet cake in a 9×13 inch pan. I know some people don’t think a 9×13 inch cake is considered a sheet cake, but I do, haha, so that’s what I’m calling it!

Since the cake itself is rich (in a great way!) I decided to use a lighter frosting – cool whip mixed with melted chocolate. It’s magical. I first fell in love with it in this healthy chocolate fudge cake recipe.

You could definitely pair this cake with chocolate buttercream, and I see myself using both frostings on this cake in the future. I’ll give you recipes for both frosting options in the recipe section below.

slice of peanut butter cake with chocolate frosting on metal plate

How to Properly Measure Flour

  • Fluff the flour with a fork
  • Use a spoon to scoop the flour into your measuring cup
  • Use a butter knife to level off the flour in the measuring cup

Sticking the measuring cup straight into the bag of flour will result in too much flour to be packed into the cup, which can result in dry cake.

Total Time Required

  • 10 minutes to prep the cake batter
  • 25 minutes to bake
  • 1+ hour to cool the cake completely
  • 5 minutes to make the frosting
slice of peanut butter cake with chocolate frosting on metal plate

How To Make Easy Chocolate Shavings

To give this cake a little pizzazz I added chocolate shavings. I literally took a hershey’s bar and used a vegetable peeler to make shavings. Instant chocolate shaving!

Frosting Options

Frost this cake with either our 2 ingredient chocolate cool whip frosting or chocolate buttercream frosting.

Chocolate Cool Whip Frosting Ingredients

  • 2 containers of cool whip 8 oz each
  • 1 cup semi-sweet chocolate chips melted

Once the melted chocolate is cool, combine the chocolate with the cool whip and spread over the cake.

Chocolate Buttercream Ingredients

  • unsalted butter
  • unsweetened natural cocoa powder
  • powdered sugar
  • heavy cream
  • salt
  • vanilla extract 

Butter, cocoa powder and powdered sugar make up the bulk of the frosting. Heavy cream is used to make the frosting extra smooth and creamy.

slice of peanut butter cake with chocolate frosting on metal plate

More Cake Recipes

3.81 from 21 ratings

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Peanut Butter Cake

By: Beth
Additional Time: 1 hour
Total Time: 1 hour
Servings: 20 servings
From scratch moist and peanut buttery PEANUT BUTTER CAKE! Pair this peanut butter cake with chocolate frosting!



  • 2 ¼ cups all purpose flour
  • 1 tsp baking soda
  • 2 tsp baking powder
  • 1 tsp salt
  • cup creamy peanut butter
  • ½ cup vegetable oil
  • 1 cup brown sugar
  • 4 large eggs
  • 1 tsp vanilla extract
  • 1 cup buttermilk

Chocolate Cool Whip Frosting

  • 1 ½ containers cool whip, 8 oz each
  • 1 cup semi-sweet chocolate chips, melted

Or Chocolate Buttercream Frosting

  • 2 sticks unsalted butter, room temperature (1 cup)
  • 1 tsp vanilla extract
  • cup cocoa powder
  • 2 cups powdered sugar
  • dash of milk or heavy cream if frosting becomes too thick



  • Preheat the oven to 350ºF. Spray a 9×13 inch pan with non-stick cooking spray.
  • In a bowl combine the flour, baking soda, baking powder, and salt. In a separate bowl, combine the peanut butter, oil, and brown sugar, beat together using an electric mixer. Add in the eggs and vanilla, beat again. Add the flour mixture and buttermilk, alternating between the two and mixing by hand until everything is incorporated.
  • Pour the batter into the 9×13 inch pan and bake for 22-25 minutes or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely before frosting.

Chocolate Cool Whip Frosting

  • Place the cup of chocolate chips in a microwave safe bowl and microwave on 50% power until melted. To help the chocolate melt without burning you can add a very small amount of oil. Allow the chocolate to cool for 5 minutes.
  • In a mixing bowl, combine the melted chocolate and cool whip, stir until combined. Spread on top of the cooled cake. The cake can be covered and refrigerated until ready to serve.

Chocolate Buttercream Topping

  • In a mixing bowl, beat the butter using an electric mixer until fluffy. Add in the vanilla extract and cocoa powder, gently mix by hand with a spatula. Begin to add the powdered sugar, about 1 cup at a time, mixing by hand.
  • Continue adding powdered sugar until the frosting no longer looks wet and tastes good to you. Then I use my electric mixer one last time to make sure the powdered sugar is really incorporated and ready to go. If the frosting becomes too thick, add a dash of milk or heavy cream. Spread on top of the cooled cake.



Choose between chocolate cool whip frosting OR chocolate buttercream frosting.


Calories: 378kcal | Carbohydrates: 47g | Protein: 7g | Fat: 20g | Saturated Fat: 10g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 6g | Trans Fat: 1g | Cholesterol: 66mg | Sodium: 298mg | Potassium: 232mg | Fiber: 3g | Sugar: 30g | Vitamin A: 390IU | Calcium: 88mg | Iron: 2mg
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About Beth

I believe that everyone should have a go-to dessert to bring to parties! With hundreds of recipes, I'll help you find yours!

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