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A spatula lifts a piece of chocolate cake topped with peanuts.
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5 from 1 vote

Chocolate Peanut Butter Sheet Cake

This Chocolate Peanut Butter Sheet Cake is a great choice for the chocolate-peanut butter lovers in your life. Sweet, simple to make, and so indulgent!
Prep Time15 mins
Cook Time25 mins
Total Time40 mins
Servings: 15


Chocolate Peanut Butter Sheet Cake:

  • 2 cups all-purpose flour
  • 2 cups sugar
  • 1 teaspoon baking soda
  • 1/2 teaspoon salt
  • 1/2 cup 1 stick butter
  • 1/2 cup creamy peanut butter
  • 1 cup water
  • 1/2 cup unsweetened cocoa powder
  • 1/2 cup sour cream
  • 3 large eggs lightly beaten
  • 2 teaspoons vanilla extract

Chocolate Peanut Butter Icing:

  • 1/2 cup 1 stick butter
  • 1/4 cup creamy peanut butter
  • 4 tablespoons unsweetened cocoa powder
  • 6 tablespoons milk I use 2%
  • 1 teaspoon pure vanilla extract
  • 3 1/2 to 4 cups powdered sugar as needed to reach desired consistency
  • 1/4 cup chopped salted peanuts


For the Chocolate Peanut Butter Sheet Cake:

  • Preheat oven to 350 degrees. Coat a 13" x 9" baking pan with non-stick cooking spray.
  • In a large bowl, whisk flour, sugar, baking soda and salt; set aside.
  • In a small saucepan, melt the butter with the peanut butter over LOW heat. Stir in the water and cocoa powder and increase heat to MEDIUM-LOW to bring just barely to a boil, stirring occasionally. Remove from heat and add to flour mixture, stirring just until moistened.
  • Add sour cream, lightly beaten eggs, and vanilla, whisking until completely incorporated. Transfer to prepared baking dish. Bake 25-30 minutes or until a toothpick inserted in center comes out clean.
  • Prepare icing while cake is baking.

For the Chocolate Peanut Butter Icing:

  • Melt butter with peanut butter in a small saucepan over LOW heat. Whisk in cocoa powder, milk and vanilla. Whisk in powdered sugar, a little at a time, until you've reached desired consistency. It should be thick but pourable. Continue whisking vigorously until powdered sugar has dissolved and icing is smooth.
  • Remove from heat and immediately pour icing over warm cake. Use an offset spatula or butter knife to spread it out evenly over the surface. Sprinkle with chopped peanuts.
  • Allow to set for at least 30 minutes or longer before slicing and serving the cake.