Chocolate Sheet Cake with Peanut Butter Frosting Recipe

Chocolate Sheet Cake with Peanut Butter Frosting is made with a rich, boiled chocolate batter that results in an incredibly moist, fudge-like sponge. The cake is baked in a large sheet pan and smothered while still warm with a smooth, sweet peanut butter glaze, allowing the frosting to melt slightly into the top crust. It is the ultimate crowd-pleasing dessert for potlucks and parties, offering a perfect marriage of salty, nutty peanut butter and deep cocoa.

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Chocolate Sheet Cake with Peanut Butter Frosting Ingredients

For the Cake:

• 3 cups All-Purpose Flour: The structural base.
• 3 cups Sugar: Granulated. It seems like a lot, but this makes a very large cake.
• 1 1/2 teaspoons Baking Soda: To leaven the dense batter.
• 1/4 teaspoon Salt: Balances the sweetness.
• 3 Large Eggs: At room temperature.
• 3/4 cup Sour Cream: Adds tang and ensures the crumb stays moist.
• 2 teaspoons Pure Vanilla Extract: Flavor base.
• 1 1/2 cups (3 sticks) Butter: Salted or unsalted.
• 3/4 cup Cocoa Powder: Unsweetened.
• 1 1/2 cups Hot Water: Blooms the cocoa.

For the Peanut Butter Frosting:

• 1/2 cup (1 stick) Butter: Melted.
• 1/2 cup Smooth Peanut Butter: Creamy is best for a glossy finish.
• 4 cups Powdered Sugar: Confectioners’ sugar, sifted.
• 1/3 cup Milk: To thin the frosting.
• 1 teaspoon Vanilla Extract: For aroma.
• 1/2 cup Chopped Walnuts: (Optional) For a crunchy finish.

How To Make Chocolate Sheet Cake with Peanut Butter Frosting

1. Prepare the pan: Preheat the oven to 350°F (175°C). Grease and flour an 18 by 13-inch rimmed baking sheet (often called a jelly roll pan). This large surface area is key to the sheet cake texture.
2. Mix dry ingredients: In a large mixing bowl, combine the flour, sugar, baking soda, and salt. Whisk briefly to aerate and distribute the leavening agents.
3. Whisk wet ingredients: In a separate medium bowl, beat the eggs. Whisk in the sour cream and vanilla extract until smooth. Add this egg mixture to the flour mixture and stir until just combined (it will be thick and doughy at this stage).
4. Boil the chocolate: In a saucepan over medium-high heat, melt the 3 sticks of butter. Stir in the cocoa powder and hot water. Bring the mixture to a boil, let it bubble for 15 seconds, and then remove from the heat. Allow it to cool slightly for a minute.
5. Combine the batter: Pour the hot chocolate mixture over the flour and egg mixture. Whisk gently but thoroughly until the ingredients are blended and the batter is smooth and pourable.
6. Bake the cake: Pour the batter into the prepared baking sheet and spread it to the edges. Bake for 25 minutes, or until a tester inserted into the center comes out clean.
7. Make the frosting: While the cake is baking (or just as it comes out), prepare the frosting. In a heavy-bottomed saucepan, melt the 1/2 cup butter over medium heat. Stir in the peanut butter until smooth and liquid. Remove from heat. In a large bowl, whisk the milk and powdered sugar together, then slowly pour in the warm peanut butter mixture and vanilla. Whisk until smooth and spreadable.
8. Frost the cake: Pour and spread the frosting over the cake while both the cake and frosting are still warm. This allows the frosting to bond with the cake and create a fudge-like interface. Sprinkle with chopped walnuts if desired. Let it set before slicing.

Recipe Tips

• Frosting Temperature: The secret to a good Texas-style sheet cake is frosting it warm. If you let the cake cool completely, the frosting will sit on top like a thick layer of paste. Frosting it warm allows it to glaze the cake beautifully.
• Sour Cream: Do not skip the sour cream. It reacts with the baking soda to create a tender crumb that contrasts with the dense, fudgy texture caused by the boiled butter method.
• Pan Size: You must use a rimmed baking sheet (jelly roll pan). If you try to bake this in a 9×13 pan, it will overflow and take forever to bake in the middle.
• Sifting Sugar: Sift the powdered sugar for the frosting to avoid white lumps. It is very difficult to whisk lumps out once the liquid is added.

What To Serve With Sheet Cake?

This cake is rich, sweet, and covers a large crowd. It pairs perfectly with a glass of ice-cold milk to wash down the peanut butter richness. For a dessert table, serve it alongside fresh fruit to cut the sugar. If you want to be extra decadent, a scoop of vanilla ice cream on top of a warm square is unbeatable.

How To Store Leftovers Sheet Cake?

• Room Temperature: This cake keeps well at room temperature, covered with foil or plastic wrap, for up to 3 days. The high sugar content acts as a preservative.
• Reheat: A 10-second zap in the microwave will return the frosting to a gooey, melting consistency.
• Freeze: Sheet cake freezes excellently. Cut into squares, wrap individually in plastic wrap, and freeze for up to 2 months.

Chocolate Sheet Cake Nutrition Facts

• Calories: ~450 kcal
• Fat: 22g
• Carbohydrates: 60g
• Protein: 5g
• Nutrition information is estimated per square based on 24 servings.

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