You’re about to discover a fantastic sheet cake recipe that brings together the classic flavors of peanut butter and chocolate. This Peanut Butter Sheet Cake with Chocolate Frosting is incredibly easy to make and perfect for any gathering, promising a moist cake and rich, creamy frosting that everyone will love.
Key Ingredients & Substitutions
- Peanut Butter: Use creamy, regular peanut butter (not natural or chunky) for the best texture.
- Buttermilk: If you don’t have buttermilk, add 1 tablespoon of white vinegar or lemon juice to regular milk and let it sit for 5 minutes.
- Cocoa Powder: Unsweetened natural cocoa powder works best for the frosting.
- Powdered Sugar: Essential for smooth frosting; don’t substitute with granulated sugar.
Ingredients
For the Cake:
- 2 cups all-purpose flour
- 2 cups granulated sugar
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 1 cup (2 sticks) unsalted butter
- 1 cup water
- 1/2 cup creamy peanut butter
- 2 large eggs
- 1/2 cup buttermilk
- 1 teaspoon vanilla extract
For the Chocolate Frosting:
- 1/2 cup (1 stick) unsalted butter
- 1/2 cup milk
- 4 tablespoons unsweetened cocoa powder
- 1 teaspoon vanilla extract
- 4 cups powdered sugar
How Much Time Will You Need?
- Total Time: 50 minutes
- Prep Time: 15 minutes
- Cook Time: 35 minutes
- Servings: 15-20 slices
- Tools Needed: 13×9 inch baking pan, large mixing bowls, saucepan, electric mixer.
Step-by-Step Instructions
1. Prepare Your Pan and Oven
Preheat your oven to 350°F (175°C). Grease and flour a 13×9 inch baking pan. This ensures your sheet cake releases easily.
2. Combine Dry Cake Ingredients
In a large bowl, whisk together the flour, granulated sugar, baking soda, and salt. Set this aside while you prepare the wet ingredients.
3. Melt Butter and Peanut Butter Mixture
In a medium saucepan, combine the butter, water, and peanut butter. Bring this mixture to a boil over medium heat, stirring until smooth. Remove from heat immediately once it boils.
4. Mix Wet and Dry Cake Ingredients
Carefully pour the hot peanut butter mixture into the dry ingredients. Stir well until just combined. Next, beat in the eggs, buttermilk, and vanilla extract until the batter is smooth.
5. Bake the Sheet Cake
Pour the batter evenly into your prepared 13×9 inch baking pan. Bake for 30-35 minutes, or until a wooden skewer inserted into the center of the sheet cake comes out clean.
6. Prepare the Chocolate Frosting
While the cake is baking, combine the butter, milk, and cocoa powder in a saucepan. Bring this to a boil, stirring constantly. Remove from heat and stir in the vanilla extract.
7. Finish the Frosting
Gradually add the powdered sugar to the hot cocoa mixture, beating with an electric mixer until smooth and creamy. The frosting should be slightly thin but spreadable.
8. Frost the Warm Cake
As soon as the sheet cake comes out of the oven, pour the warm frosting over it. Spread it quickly and evenly to cover the entire cake. The warmth of the cake will help the frosting melt slightly and create a delicious glaze. Let it cool completely before serving.
Variation Ideas
- Sprinkle with chopped roasted peanuts before the frosting sets.
- Add a layer of mini chocolate chips to the cake batter for extra chocolate.
- Dust with a little extra cocoa powder on top for a finishing touch.
Storage Instructions
Store your leftover Peanut Butter Sheet Cake at room temperature in an airtight container for up to 3 days. You can also refrigerate it for up to a week, but let it come to room temperature before serving for the best texture.
Frequently Asked Questions (FAQ)
Q: Can I use natural peanut butter for this sheet cake recipe?
A: It’s best to use creamy, processed peanut butter. Natural peanut butter can separate and affect the cake’s texture.
Q: Why do you pour the frosting on a warm cake?
A: Pouring the frosting on a warm sheet cake helps it spread smoothly and creates a slightly melty, delicious glaze.
Q: Can I make this cake ahead of time?
A: Yes, this sheet cake can be made a day in advance. Cover it tightly and store at room temperature.
Q: My frosting seems too thin/thick. What should I do?
A: If it’s too thin, add a little more powdered sugar. If it’s too thick, add a tiny bit of milk, one teaspoon at a time, until it reaches the desired consistency.
Q: What size pan should I use for this sheet cake recipe?
A: This recipe is designed for a standard 13×9 inch baking pan. Using a different size will affect baking time and thickness.