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Peanut Butter Sheet Cake with Fluffy Peanut Butter Frosting

A soft, moist peanut butter sheet cake topped with ultra-fluffy peanut butter frosting. Easy to make, perfect for crowds, and packed with peanut butter flavor.
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Prep Time 15 minutes
Cook Time 22 minutes
Total Time 37 minutes
Servings: 20 squares
Course: Cake, Dessert
Cuisine: American
Calories: 285

Ingredients
  

Cake
  • 2 cups all-purpose flour
  • 1.5 cups sugar
  • 1 tsp baking soda
  • 0.5 tsp salt
  • 1 cup water
  • 0.5 cup milk
  • 0.5 cup butter unsalted
  • 0.5 cup creamy peanut butter
  • 2 eggs
  • 1 tsp vanilla extract
Fluffy Peanut Butter Frosting
  • 0.5 cup butter softened
  • 0.75 cup creamy peanut butter
  • 3 cups powdered sugar
  • 0.25 cup heavy cream
  • 1 tsp vanilla extract
  • 1 pinch salt

Equipment

  • Jelly roll pan
  • Saucepan
  • Mixing bowls
  • Electric mixer

Method
 

  1. Preheat oven to 350°F and grease a 10×15 jelly roll pan.
  2. Whisk together flour, sugar, baking soda, and salt.
  3. Heat butter, peanut butter, and water until melted; pour into dry ingredients.
  4. Mix in eggs, milk, and vanilla until smooth.
  5. Bake 18–22 minutes until a toothpick comes out clean.
  6. Beat butter and peanut butter; add powdered sugar, cream, and vanilla to make frosting.
  7. Spread frosting over cooled cake and garnish as desired.

Notes

Do not use natural peanut butter for best texture. Add peanuts or chocolate chips for extra crunch.