This Peanut Butter Sheet Cake is the stuff of peanut butter lovers’ dreams! Satisfy your peanut butter and dessert cravings in one moist and tender cake topped with the most delicious peanut butter marshmallow icing.
Peanut Butter Sheet Cake with Peanut Butter Icing
Whenever I’m craving peanut butter (which is often, let’s be honest), this peanut butter sheet cake is my go-to. It checks all the boxes needed to satisfy the craving: perfectly moist, the exact right amount of peanut butter flavor, and of course a sweet and creamy peanut butter frosting.
Some peanut butter cakes or cookies can get dry or crumbly. That is NOT the case here. Along with an incredibly tender texture that melts in your mouth it’s topped with creamy marshmallow peanut butter frosting. Everyone always raves about the frosting!
Anywhere it goes, this easy cake is a hit with peanut butter lovers, and just about everyone else. Bake it, freeze it, or enjoy it fresh for days! Snacking cakes don’t get more delicious than this.
Why You’ll Love This Peanut Butter Cake
- Easy. You won’t need any complicated ingredients or fancy techniques to make this recipe. That’s the beauty of a sheet cake, it’s ridiculously simple!
- Full of peanut butter flavor. Peanut butter is infused into the cake and the icing, so every bite of this dessert is bursting with rich peanut butter flavor.
- Perfect texture. Every slice is tender, moist and fluffy. Did I mention this cake is 100% irresistible?
- Ideal for potlucks! This cake is perfect for serving a crowd. For this reason, I love bringing it to potlucks and family gatherings!
What You’ll Need
Here’s a quick look at what you’ll need to make this peanut butter cake. Be sure to scroll down to the recipe card for specific amounts.
- Peanut Butter: You can use creamy peanut butter, or crunchy peanut butter for added texture! The choice is yours. You’ll need it for both the cake as well as the marshmallow peanut butter icing.
- Buttermilk: This is the not-so-secret ingredient for cake that’s super moist and tender! Plus, the flavor adds a bit of tang. No buttermilk in the fridge? Check out my buttermilk substitute tutorial.
- Butter: Unsalted or salted, cut into cubes, plus extra for the icing.
- Large Eggs
- Vanilla: Pure vanilla extract is best for flavor, but imitation will also work in a pinch.
- Vegetable Oil: Or another neutral cooking oil, like canola.
- Evaporated Milk: Adds extra sweetness and smoothness to the icing.
- Mini Marshmallows: The base for the delicious marshmallow and peanut butter icing!
- Granulated Sugar
- Dry Ingredients: All Purpose Flour, Baking Soda, and Salt
How to Make Peanut Butter Cake
Are you ready to make the best peanut butter sheet cake? Here’s how to do it:
- Mix the Batter: Set aside the flour and dry ingredients in one bowl, and the buttermilk and wet ingredients in another. Next, you’ll prep the peanut mixture by bringing water and butter to a boil, and stirring in the peanut butter and oil. Add the peanut mixture to the flour mixture, followed by the buttermilk mixture, whisking as you go.
- Bake the Cake: Pour the batter into a lined jelly-roll style pan. Bake the cake in the oven until the center is set and it passes the toothpick test (a toothpick inserted into the middle comes out clean).
- Cool. Let the cake cool for a bit so that it doesn’t melt the icing. If you can let it cool to room temperature that’s ideal!
- Make the Icing: Bring the evaporated milk, sugar, salt and butter to a boil while continuously stirring. Once this is taken off the heat, melt in the peanut butter and marshmallows. While the cake is still warm, pour the icing over top. Use a spatula to spread it evenly across the cake, then leave it to cool. Once the cake is cooled completely, slice and serve!
Tips for the Best Peanut Butter Cake
- Can I Use a Smaller Pan?: If you’d prefer to make this peanut butter cake in a 9×13 inch pan, it will still be delicious! Just increase the baking time to 35-40 minutes to account for the extra thickness.
- If the Peanut Butter Mixture Is Really Hot: Adding the peanut butter mixture to the flour first should be enough to cool it off before it’s combined with the eggs/wet ingredients. However, if you’re concerned that the mixture is still hot enough to start cooking the eggs, leave it for a few minutes to cool before going ahead with the recipe as directed.
- Can I Use Natural Peanut Butter? I’d recommend sticking to Jiffy peanut butter for this sheet cake. Natural peanut butters have a tendency to separate, which can lead to mixed results.
I like to think of a sheet cake as my own personal canvas for all sorts of toppings! While this peanut butter cake is delicious all on its own, there are so many topping ideas you can choose from, too:
- Mini peanut butter cups
- Chocolate chips or white chocolate chips
- Chopped nuts like peanuts, pecans, hazelnuts, or macadamia
- Extra mini marshmallows
- A drizzle of Hot Fudge Sauce or Homemade Caramel Sauce
How to Store:
Store peanut butter cake airtight at room temperature for up to 3 days. If you’d like to extend the shelf-life, keep it covered in the fridge for up to 4-5 days.
Can I Freeze This Cake?
To freeze this peanut butter cake (and to avoid messing up the icing), once it’s cooled completely, pop the whole pan into the freezer to pre-freeze. When the sheet cake is frozen solid, wrap it in a double layer of plastic wrap plus an extra layer of foil. The cake can stay frozen for up to 3 months!
Thaw the cake overnight in the refrigerator before carefully unwrapping it. Voila! Your pre-made cake is ready to serve.
More Peanut Butter Dessert Ideas:
- Swirled Peanut Butter Cup Cookies
- Outrageous Peanut Butter Candy Bars
- Classic Peanut Butter Blossoms
- Peanut Butter Cup Blondies
- No Bake Chocolate & Honey Peanut Butter Bars
The stuff of peanut butter lovers’ dreams! You’ll love serving up a slice of this dreamy Peanut Butter Sheet Cake topped with peanut butter marshmallow icing. Perfect for gatherings and potlucks!
For the Cake:
- 2 cups all purpose flour
- 2 cups granulated sugar
- 1 teaspoon baking soda
- 1/2 teaspoon kosher salt
- 2 large eggs
- 1 teaspoon vanilla extract
- 1/2 cup buttermilk
- 1 cup water
- 3/4 cup butter, cut into cubes
- 1/2 cup peanut butter (crunchy or creamy)
- 1/4 cup vegetable oil
For the Icing:
- 1/3 cup evaporated milk
- 2/3 cup granulated sugar
- 1/4 teaspoon kosher salt
- 2 tablespoons butter
- 1/3 cup peanut butter (creamy or crunchy)
- 1/2 cup mini marshmallows
- 1 teaspoon vanilla extract
Make the Cake
- Preheat your oven to 350°F. Line a 15x10x1 (jelly roll-style) pan with parchment paper. Coat with nonstick spray and set aside.
- In a large bowl whisk together the flour, sugar, baking soda, and salt. Set aside.
- In a small bowl whisk together the eggs, vanilla, and buttermilk. Set aside.
- Place water and butter in a small saucepan over medium heat. Bring to a boil and remove from the heat. Stir in the peanut butter and oil, mixing until combined. Add this into the flour mixture and whisk until smooth. Then whisk in the buttermilk mixture until evenly blended.
- Pour the batter into the prepared pan and bake for 20 – 25 minutes until the center is set and a toothpick inserted comes out clean.
Make the Icing
- Stir together the evaporated milk, granulated sugar, salt, and butter in a medium sauce. Bring to a boil over medium heat, and boil for 2 minutes stirring constantly. Remove from the heat and stir in the peanut butter, marshmallows, and vanilla until combined and the marshmallows are melted.
- Pour the icing onto the warm cake, spreading out evenly using an offset spatula.
- Allow the cake to cool completely before slicing and serving.
Store airtight at room temperature for up to 3 days.
Keywords: peanut butter cake, peanut butter sheet cake, peanut butter cake recipe
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