Peanut Butter Sheet Cake with Peanut Butter Frosting

 

A rich, moist sheet cake packed with creamy peanut butter flavor and topped with a silky peanut butter frosting that melts in your mouth. This is a crowd-pleasing dessert that’s easy to make and perfect for any occasion—birthdays, potlucks, picnics, or simply to satisfy a peanut butter craving!

 Ingredients

For the Cake

• 2 cups all-purpose flour
• 1 ½ cups granulated sugar
• 1 teaspoon baking soda
• ½ teaspoon salt
• 1 cup unsalted butter
• 1 cup water
• ½ cup creamy peanut butter
• ½ cup whole milk
• 2 large eggs
• 1 teaspoon vanilla extract

For the Peanut Butter Frosting

• ½ cup unsalted butter
• ½ cup creamy peanut butter
• ¼ cup whole milk
• 2 ½ cups powdered sugar
• 1 teaspoon vanilla extract
• Pinch of salt (optional, enhances flavor)

 Prep & Cooking Time

• Prep Time: 15 minutes
• Cook Time: 25 minutes
• Total Time: 40 minutes
• Servings: About 12–16

 Instructions

 Step 1: Preheat the Oven

• Preheat your oven to 350°F (175°C).
• Grease and flour a 9×13-inch sheet cake pan or line it with parchment paper for easy removal.

 Step 2: Mix the Dry Ingredients

• In a large mixing bowl, whisk together:
  • 2 cups flour
  • 1 ½ cups sugar
  • 1 teaspoon baking soda
  • ½ teaspoon salt
• Set this dry mixture aside.

 Step 3: Prepare the Peanut Butter Mixture

• In a medium saucepan over medium heat, combine:
  • 1 cup butter
  • 1 cup water
  • ½ cup peanut butter
• Stir constantly until everything is melted and the mixture is smooth and uniform.
• Once smooth, remove from heat and let it cool slightly.

 Step 4: Combine Everything

• Pour the warm peanut butter mixture into the dry ingredients.
• Mix until just combined (no dry streaks).
• Add:
  • ½ cup milk
  • 2 eggs
  • 1 teaspoon vanilla extract
• Stir until the batter is smooth and creamy.

 Step 5: Bake the Cake

• Pour the batter into the prepared 9×13-inch pan.
• Bake for 20–25 minutes, or until a toothpick inserted into the center comes out clean.
• Place the pan on a wire rack and allow the cake to cool completely before frosting.

 Make the Peanut Butter Frosting

 Step 6: Prepare the Frosting Base

• In a small saucepan over medium heat, melt together:
  • ½ cup butter
  • ½ cup peanut butter
  • ¼ cup milk
• Stir until smooth. Do not let it boil.

 Step 7: Whip the Frosting

• Remove from heat and gradually whisk in:
  • 2 ½ cups powdered sugar
  • 1 teaspoon vanilla extract
  • A pinch of salt, if desired
• Beat until smooth and creamy. Add a splash more milk if the frosting is too thick.

 Step 8: Frost the Cake

• While the frosting is still slightly warm (not hot), pour it over the cooled cake.
• Use an offset spatula or the back of a spoon to spread it evenly.
• Let the frosting set for about 10–15 minutes before slicing.

 Tips for Success

• Use room temperature eggs to help the batter blend better.
• Don’t overbake: The cake should be soft and moist. Watch carefully around the 20-minute mark.
• For deeper flavor, you can toast the peanut butter in the pan for a minute before adding the other wet ingredients.
• Sprinkle chopped roasted peanuts on top of the frosting for added crunch and flair.

 Serving Suggestions

• Serve this cake at room temperature for the best texture.
• It pairs perfectly with a cold glass of milk or a hot cup of coffee.
• Cut into small squares for bite-sized party servings, or large slabs for dessert lovers!

 Storage

• Store the cake covered at room temperature for up to 3 days.
• For longer storage, keep it in the refrigerator (up to 5 days), but allow it to come to room temp before serving for best flavor and softness.
• You can also freeze unfrosted cake for up to 2 months. Wrap tightly and thaw before frosting.

 Final Thoughts

This Peanut Butter Sheet Cake is old-fashioned comfort in dessert form—moist, flavorful, and packed with peanut buttery goodness. It’s the kind of simple yet satisfying cake that disappears fast at gatherings, potlucks, and family dinners.