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Peanut Butter Sheet Cake with Creamy Frosting
Caroline

Peanut Butter Sheet Cake with Creamy Frosting

A rich and moist peanut butter sheet cake topped with a creamy peanut butter frosting. Easy to make, crowd-pleasing, and perfect for birthdays, potlucks, or weeknight desserts.
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Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes
Servings: 12 squares
Course: Dessert
Cuisine: American
Calories: 480
Ingredients Equipment Method Notes

Ingredients
  

  • 1 box yellow cake mix
  • 4 large eggs
  • 0.5 cup unsalted butter, softened
  • 1 cup creamy peanut butter
  • 1 cup water
  • 0.5 cup unsalted butter, softened (for frosting)
  • 1 cup creamy peanut butter (for frosting)
  • 4 cups powdered sugar
  • 0.25 cup milk
  • 1 tsp vanilla extract

Equipment

  • mixing bowls
  • Electric mixer or hand whisk
  • 9x13-inch sheet cake pan
  • spatula
  • Cooling rack

Method
 

  1. Preheat oven to 350°F (175°C). Grease and lightly flour a 9x13-inch cake pan.
  2. In a large mixing bowl, combine cake mix, eggs, softened butter, creamy peanut butter, and water. Beat until smooth and well combined.
  3. Pour batter into the prepared pan. Bake for 25–30 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool completely.
  4. In a medium bowl, beat softened butter and peanut butter until smooth. Gradually add powdered sugar, alternating with milk, until fluffy. Stir in vanilla.
  5. Spread the frosting evenly over the cooled cake.
  6. Slice into squares and serve fresh.

Notes

  • This cake is best served at room temperature to keep the frosting creamy.
  • If you want a thicker frosting layer, double the frosting recipe.
  • To cut clean slices, dip your knife in hot water, wipe dry, then cut through the cake.