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Peanut Butter Sheet Cake With Peanut Butter Frosting

The scent of peanut butter always brings me back to childhood summers. My grandmother, a woman who believed everything tasted better with peanut butter, used to bake a simple sheet cake. It wasn’t fancy, but the aroma of that cake wafting through her sun-drenched kitchen is a sensory memory I treasure. This recipe, while a touch more indulgent than Grandma’s, captures that same comforting essence, making it a guaranteed crowd-pleaser for any occasion.

Recipe Overview

Prep Time: 15 minutes
Cook Time: 18-25 minutes
Total Time: 33-40 minutes
Servings: 30 (estimated)
Yield: 1 (10×15 inch) sheet cake
Dietary Type: Not specified

Ingredients

CAKE

2 cups flour
1 cup white sugar
1 cup light brown sugar, packed (or use 2 cups white sugar)
½ teaspoon baking soda
¼ teaspoon salt
½ teaspoon cinnamon (optional)
1 cup water
¾ cup butter, softened
½ cup smooth peanut butter
¼ cup vegetable oil
2 eggs
½ cup buttermilk
2 teaspoons vanilla

FROSTING

½ cup butter, softened (no substitutes)
1 cup creamy peanut butter
4 cups confectioners’ sugar
⅓ cup whipping cream, unwhipped (or use 18% table cream)
2 teaspoons vanilla

Equipment Needed

10 x 15-inch jellyroll pan
Parchment paper
Large mixing bowl
Saucepan
Electric mixer (handheld or stand mixer)
Measuring cups and spoons

Instructions

Preheat your oven to 350°F (175°C) and position the oven rack to the second-lowest position. This ensures even baking.
Line the bottom of a 10 x 15-inch jellyroll pan with parchment paper. This will prevent the cake from sticking and make it easy to remove. Leave a little overhang on the sides to act as handles.
In a large bowl, stir together 2 cups flour, 1 cup white sugar, 1 cup light brown sugar (or 2 cups white sugar if preferred), ½ teaspoon baking soda, ¼ teaspoon salt, and ½ teaspoon cinnamon (if using). Make sure everything is well combined.
In a saucepan, combine 1 cup water with ¾ cup butter. Bring the mixture to a boil over medium heat. Once boiling, remove the saucepan from the heat.
Stir in ½ cup smooth peanut butter and ¼ cup vegetable oil into the hot butter mixture. Mix until everything is completely blended and smooth.
Pour the peanut butter mixture into the dry flour mixture in the large bowl. Stir until just combined. Be careful not to overmix at this stage.
In a separate bowl, mix together 2 eggs with ½ cup buttermilk and 2 teaspoons vanilla until completely combined. A whisk works well for this.
Add the egg mixture to the peanut butter/flour mixture. Stir until just combined. The batter will be quite thin, which is perfectly normal.
Pour the batter into the prepared pan and spread it evenly.
Bake for 18-25 minutes, or until the cake tests done. To check for doneness, insert a toothpick into the center of the cake. If it comes out clean or with just a few moist crumbs, the cake is ready. Watch closely, as this cake tends to bake quickly.
Cool the cake in the pan completely before frosting. This prevents the frosting from melting.
For the frosting, in a large bowl, beat ½ cup butter with 1 cup creamy peanut butter and 2 teaspoons vanilla until light and fluffy. An electric mixer is your best friend here.
Beat in ⅓ cup whipping cream until combined. Start on low speed to avoid splattering.
Add in ½ cup confectioners’ sugar to start, then gradually beat in the remaining 3 ½ cups confectioners’ sugar, adding in more if necessary to achieve the desired consistency. You might need a little more or less depending on the humidity in your kitchen.
Spread the frosting evenly over the cooled cake.

Expert Tips & Tricks

For a richer, more intense peanut butter flavor, use natural peanut butter (the kind you have to stir). Just be sure it’s well-stirred before adding it to the recipe.
If you don’t have buttermilk on hand, you can easily make a substitute by adding 1 ½ teaspoons of lemon juice or white vinegar to ½ cup of regular milk. Let it stand for 5 minutes before using.
To prevent the cake from sticking to the pan, you can also grease and flour the pan in addition to using parchment paper.
Don’t overbake the cake! Overbaking will result in a dry cake. Err on the side of slightly underbaked, as it will continue to cook slightly as it cools.
For a decorative touch, sprinkle chopped peanuts or peanut butter chips over the frosting.
If your frosting is too thick, add a tablespoon of milk or cream at a time until you reach the desired consistency. If it’s too thin, add a tablespoon of confectioners’ sugar at a time.
For easy cleanup, spray your measuring cups and spoons with cooking spray before measuring the peanut butter. It will slide right out!

Serving & Storage Suggestions

Serve the peanut butter sheet cake at room temperature. Cut into squares or rectangles, depending on your preference. This cake is excellent on its own, but it can also be served with a scoop of vanilla ice cream or a dollop of whipped cream.

Leftover cake can be stored in an airtight container at room temperature for up to 3 days. For longer storage, refrigerate for up to a week. You can also freeze the cake for up to 2 months. Thaw overnight in the refrigerator before serving. To maintain the cake’s moisture when storing, press a piece of plastic wrap gently against the cut surfaces.

Nutritional Information

Note: Nutritional information is an estimate and may vary based on specific ingredients and serving size.

Nutrient	Amount per Serving	% Daily Value
Calories	323 kcal	N/A
Calories from Fat	156 kcal	N/A
Total Fat	17.4 g	26%
Saturated Fat	7.2 g	36%
Cholesterol	36.5 mg	12%
Sodium	180 mg	7%
Total Carbohydrate	39.1 g	13%
Dietary Fiber	1 g	4%
Sugars	30.9 g	N/A
Protein	4.8 g	9%

Variations & Substitutions

Chocolate Peanut Butter: Add ½ cup of cocoa powder to the dry ingredients for a chocolate twist.
Peanut-Free Version: Substitute the peanut butter in the cake with sunflower seed butter or almond butter. For the frosting, use a vanilla buttercream frosting.
Gluten-Free: Use a gluten-free flour blend in place of the all-purpose flour. You may need to add a binder, like xanthan gum, to help with the structure.
Dairy-Free: Use a dairy-free butter substitute and a dairy-free milk alternative (like almond milk or soy milk) in place of the buttermilk and whipping cream.
Spiced Peanut Butter: Add a pinch of nutmeg or ginger to the dry ingredients for a warm, spiced flavor.

FAQs (Frequently Asked Questions)

Q: Can I use crunchy peanut butter instead of creamy?
A: While you can, the creamy peanut butter will give a smoother texture to both the cake and the frosting. If you do use crunchy, expect a slightly more textured result.

Q: My cake is browning too quickly. What should I do?
A: If the top of your cake is browning too quickly, tent it loosely with aluminum foil to shield it from the heat.

Q: Can I make this cake ahead of time?
A: Absolutely! The cake can be baked, cooled, and stored (unfrosted) in an airtight container for a day or two before frosting. The frosted cake can also be stored in the refrigerator for a few days.

Q: What if I don’t have a 10×15 inch pan?
A: You can use a 9×13 inch pan, but the baking time may need to be increased slightly. Keep a close eye on it. The cake will also be thicker.

Q: Can I freeze the frosting?
A: While it’s possible, the texture of the frosting may change slightly after freezing and thawing. It’s best to make the frosting fresh for the best results.

Final Thoughts

This Peanut Butter Sheet Cake with Peanut Butter Frosting is more than just a dessert; it’s a hug in cake form. The moist, tender crumb and the intensely peanut buttery frosting create a symphony of flavors that will have everyone reaching for a second slice. I encourage you to gather your ingredients, preheat your oven, and embark on this baking adventure. Don’t be afraid to experiment with the variations and substitutions to make it your own. And most importantly, enjoy the process and the delicious results! This cake is perfect with a cold glass of milk or a hot cup of coffee. Let me know in the comments how your cake turns out!

Peanut Butter Sheet Cake With Peanut Butter Frosting Recipe