This peanut butter sheet cake recipe brings together a moist sheet cake chock-full of peanut butter flavor with a decadent, creamy peanut butter frosting that has a touch of marshmallow flavor.
If you have a lot of peanut butter fans in your house, you may want to make two of these!
The cake itself is super simple to make with just a handful of steps. While it’s baking, you can whip up the frosting on the stovetop — and you can even pour it directly on the cake when it comes out of the oven.
If you’re looking for the best peanut butter sheet cake to satisfy your sweet tooth, give this irresistible cake a try.
Why You’ll Love Peanut Butter Sheet Cake
If you’re a fan of peanut butter, this cake may become your go-to sweet treat.
- Delicious – Peanut butter lovers are going to adore this incredible cake that has peanut butter in both the cake itself and the frosting.
- Show-stopper – Everyone will want to stop to grab a slice of this impressive cake.
- Versatile – You can make this cake for casual family gatherings or for special occasions.
Ingredients
While the list may look a little long, there is some overlap between the cake ingredients and frosting ingredients. Additionally, all of these are easy to find at the grocery store if you don’t already have them.
- All-purpose flour – All-purpose flour is the ideal type to use for this recipe but you can experiment with alternative flours.
- White sugar – Granulated sugar contributes to the sweet flavor of the cake.
- Brown sugar – Brown sugar adds molasses-style flavor.
- Baking soda – This leavening agent helps the cake to rise.
- Baking powder – Baking powder also contributes to the rise and texture of the cake.
- Fine sea salt – Sea salt enhances the flavors of the sugars, vanilla, and peanut butter.
- Creamy peanut butter – Creamy peanut butter will be easier to mix than chunky peanut butter and results in the most smooth texture. We do not recommend using all-natural peanut butter with the oil that separates in the jar..
- Milk – We recommend using full-fat milk for the best flavor and texture.
- Vanilla extract – Vanilla balances the flavors in the cake.
- Large eggs – Eggs help to build the structure of the cake.
- Vegetable oil – This is the standard oil we use when baking but you can replace it with another neutral flavored oil.
- Evaporated milk – Evaporated milk helps to make the frosting creamy.
- Unsalted butter – Butter adds richness to the frosting.
- Mini marshmallows – The marshmallows add their own distinctive flavor.
How To Make Peanut Butter Sheet Cake
Peanut Butter Cake
- Cream. Add the peanut butter and sugar to the large bowl of a stand mixer with a paddle attachment (or a large mixing bowl if using an electric hand mixer). Beat the ingredients until smooth and fluffy, scraping the sides of the bowl and the bottom of the bowl to incorporate.
- Wet Ingredients. Add the wet ingredients and mix until completely combined.
- Sift. In a separate bowl, combine flour with the other dry ingredients by whisking or sifting them into the bowl.
- Dry Ingredients. Add the flour mixture to the peanut butter mixture and mix together until the dry ingredients are moistened. For a moist cake, take care not to overmix.
- Bake. Transfer the peanut butter cake batter to the prepared sheet cake pan sprayed with cooking spray and bake until a toothpick inserted into the center comes out clean.
Marshmallow Frosting
- Heat & Mix. Add the sugar, butter, and evaporated milk to a medium saucepan and stir constantly until the sugar dissolves. Reduce the heat and add the marshmallows, vanilla, and peanut butter. Continue stirring until silky smooth.
- Pour. Carefully pour the still-warm frosting over top of the hot cake. Spread peanut butter icing so that it is in an even layer using an offset spatula.
- Garnish. Immediately top with the peanuts, then allow the cake to cool to room temperature on a wire rack.
What to Serve With Peanut Butter Sheet Cake
This cake needs no pairing to be the perfect dessert! However, you can always serve it with a dollop of whipped cream, a scoop of ice cream, a cold glass of milk, or a hot cup of coffee.
For the over-21 crowd, you can also shake or stir some adult beverages like an espresso martini or a white chocolate martini.
Variations
- Nuts – Choose your own favorite type of nut to sprinkle on top.
- Candy – Add chopped Reese’s Peanut Butter Cups to the top of the cake.
- Chocolate – Drizzle melted chocolate over the top or add chocolate chips.
- Frosting – Top with a chocolate frosting or another favorite flavor.
- Confectioner’s sugar – Dust the top of the cake with a little bit of powdered sugar.
Storage and Freezing
You can wrap the unfrosted sheet cake in plastic wrap and store at room temperature for 2-4 days.
Make ahead: While we do like to add the icing to the warm cake for this specific recipe, you can make the cake ahead of time and wrap it tightly until ready to frost.
Refrigerator: Store the cake in the fridge in an airtight container for up to 1 week.
Freezer: Freeze the cake for up to 3 months.
Common Questions About Peanut Butter Sheet Cake
Regular cake is typically made in a standard-size baking dish (9×13), while sheet cake is made in a larger sheet pan that tends to be shallow.
You can add decorations to the cake, like sprinkles, decorator’s sugar, or nuts. You can also pull out your pastry bag and pipe decorative icing on top.
You make a sheet cake up to 2 days ahead of time as long as you store it tightly wrapped in plastic wrap.
More Easy Cakes
Peanut Butter Sheet Cake
Equipment
- heavy bottom saucepan
Ingredients
- 1 cup granulated sugar
- 1 cup brown sugar- lightly packed
- 1 cup smooth peanut butter
- 1 ¼ cup milk
- 2 teaspoons vanilla
- 2 eggs
- ¼ cup vegetable oil
- 2 ¼ cup flour
- 1 teaspoon baking soda
- 1 teaspoon baking powder
- ¼ tsp salt
Marshmallow Frosting:
- 2/3 cup sugar
- 1/3 cup evaporated milk
- 1 tablespoon butter
- 3/4 cup creamy peanut butter
- 1/2 cup miniature marshmallows
- 1 1/2 teaspoons vanilla
Topping:
- 1/4 cup honey roasted peanuts coarsely chopped
Instructions
- Preheat your oven to 350°F. and prepare a 9×13 baking pan by spraying generously with non-stick spray and set aside.
- In the bowl of a stand mixer equipped with a paddle attachment, cream the peanut butter and both sugars until light and fluffy.
- Scrape the sides and bottom of the bowl and ad in the milk, vanilla, eggs, and oil, and mix until well combined.
- Sift in the flour, baking soda, baking powder, and salt and mix until there are no dry spots remaining.
- Pour the cake batter into the prepared pan and bake for 25-30 minutes or until a toothpick inserted in the center of the cake comes out clean. Remove from the oven and frost immediately.
MARSHMALLOW FROSTING:
- About 5 minutes before the cake is scheduled to be removed from the oven start to make the frosting.
- In a medium saucepan, combine the sugar, evaporated milk and butter and heat over medium-high, stirring continuously.
- When sugar is dissolved, add the peanut butter, marshmallows and vanilla. Stir until smooth and fully incorporated over very low heat.
- Pour warm frosting mixture over the hot Peanut Butter Cake and spread around to cover fully. Sprinkle with honey roasted peanuts immediately while frosting is still tacky.
- Allow to cool completely before serving.
- If you’ve tried this recipe, come back and let us know how it was in the comments or ratings.
Sara Welch
Enjoyed this for dessert last night and it was a sweet success! Easy, fluffy and delicious; my whole family loved it!
Justine
I made this for my birthday and it was a huge hit! Sweet and fluffy, everybody loved it!
Elisa
Will try and make this Peanut Butter Sheet Cake recipe, looks fluffy and delicious. Thanks for sharing 🙂
Sophie
This Peanut Butter Sheet Cake is a peanut butter lover’s dream – it disappeared within minutes at our last gathering!
nancy
i am obsessed with this easy peanut butter dessert. It was so easy to make and everyone loved it at work.