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Peanut Butter Sheet Cake with Peanut Butter Frosting
Sarah namedy

Peanut Butter Sheet Cake with Peanut Butter Frosting

This rich and moist peanut butter sheet cake is topped with a creamy peanut butter frosting, making it a dream dessert for peanut butter lovers. Perfect for potlucks, birthdays, or any occasion where you need a crowd-pleasing treat.
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Prep Time 20 minutes
Cook Time 30 minutes
Total Time 50 minutes
Servings: 16 squares
Course: Dessert
Cuisine: American
Calories: 420
Ingredients Equipment Method Notes

Ingredients
  

  • 1 cup creamy peanut butter
  • 1 cup unsalted butter, softened
  • 2 cups granulated sugar
  • 4 large eggs
  • 1 tsp vanilla extract
  • 2 cups all-purpose flour
  • 1 tsp baking powder
  • 1/2 tsp baking soda
  • 1/2 tsp salt
  • 1 cup buttermilk
  • 1/2 cup creamy peanut butter (for frosting)
  • 1/2 cup unsalted butter, softened (for frosting)
  • 4 cups powdered sugar
  • 1/4 cup milk (more if needed)
  • 1 tsp vanilla extract (for frosting)

Equipment

  • 13x18-inch sheet pan
  • Large mixing bowl
  • Medium mixing bowl
  • Whisk
  • electric mixer or hand whisk
  • Measuring cups and spoons
  • Spatula
  • Oven

Method
 

  1. Preheat your oven to 350°F (175°C). Grease and flour a 13x18-inch sheet pan.
  2. In a large bowl, cream together the peanut butter, butter, and sugar until light and fluffy. Add eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
  3. In another bowl, whisk together flour, baking powder, baking soda, and salt.
  4. Gradually add the dry ingredients to the peanut butter mixture, alternating with buttermilk, starting and ending with the dry ingredients. Mix until just combined.
  5. Pour the batter into the prepared sheet pan and smooth the top. Bake for 25–30 minutes, or until a toothpick inserted into the center comes out clean. Let cool completely in the pan.
  6. In a medium bowl, beat together the peanut butter and butter until smooth. Gradually add powdered sugar and milk, mixing until creamy. Stir in the vanilla extract.
  7. Once the cake has cooled, spread the peanut butter frosting evenly over the top.
  8. Cut into squares and enjoy!

Notes

For extra flavor, top with chopped peanuts or drizzle with melted chocolate. Store leftovers covered at room temperature for 2 days or refrigerate up to 5 days. This cake also freezes well (without frosting) for up to 2 months.