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–+ servings
Peanut butter cake topped with chocolate frosting on small white plate.
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Peanut Butter Sheet Cake

This peanut butter sheet cake is packed with as much peanut butter as possible for a truly phenomenal taste and texture!
Course Dessert
Cuisine American
Prep Time 20 minutes
Cook Time 15 minutes
Cooling Time 1 hour
Total Time 1 hour 35 minutes
Servings 16 servings
Calories 541kcal
Author Karly Campbell

Ingredients

For the cake:

  • 1 1/2 cups granulated sugar
  • 1/2 cup brown sugar
  • 2 cups flour
  • 1 teaspoon baking soda
  • 1 teaspoon salt
  • 1 1/2 cups milk divided
  • 1 cup creamy peanut butter
  • 1 cup butter
  • 2 teaspoons vanilla
  • 2 large eggs

For the frosting:

  • 1 cup granulated sugar
  • 1/3 cup butter
  • 1/3 cup milk
  • 1/2 cup creamy peanut butter
  • 3/4 cup semi-sweet chocolate chips

Instructions

To make the cake:

  • Preheat oven to 400 degrees. Grease a rimmed half sheet pan.
  • Add the sugars, flour, baking soda, and salt to a mixing bowl and whisk to combine.
  • Add 1 cup of milk, peanut butter, and butter to a small sauce pan and bring to a boil, stirring often.
  • Remove from heat and let set for 5 minutes to cool. Add to the dry ingredients.
  • Add the remaining 1/2 cup of milk, vanilla, and eggs to the bowl and use an electric mixer to beat together on low speed until the batter is smooth and well combined.
  • Spread cake batter into prepared baking sheet and bake for 15 minutes. Cool completely, about an hour.

To make the frosting:

  • Add the sugar, butter, and milk to a small sauce pan and stir well. Bring to a boil and boil for exactly 60 seconds.
  • Remove from the heat and stir in the peanut butter and chocolate chips until smooth and melted.
  • Pour warm frosting over the cooled cake and spread with a spatula. Frosting will harden as it cools.
  • Cut and serve once frosting has cooled and set.

Notes

Be sure to use a processed peanut butter, like Jif or Skippy, and not the natural kind that separates and has to be stored in the fridge.
Be sure to cool the peanut butter mixture a bit before mixing with the other ingredients so that you don't accidentally scramble the eggs with the hot mixture.
The frosting will seem a bit runny, but it will firm up as it cools. 
For a thicker layer of frosting, double the frosting recipe.
 

Nutrition

Serving: 1slice | Calories: 541kcal | Carbohydrates: 59g | Protein: 9g | Fat: 31g | Saturated Fat: 14g | Cholesterol: 67mg | Sodium: 483mg | Potassium: 263mg | Fiber: 2g | Sugar: 43g | Vitamin A: 550IU | Calcium: 62mg | Iron: 1.7mg