Peanut Butter Sheet Cake with Fluffy Peanut Butter Frosting: A Classic Dessert

If you love peanut butter in all its creamy glory, this Peanut Butter Sheet Cake with Fluffy Peanut Butter Frosting is your ultimate dessert. Rich, moist, and tender, the cake is complemented by a light and airy peanut butter frosting that melts in your mouth. This easy-to-make sheet cake is perfect for birthdays, potlucks, or anytime you crave a sweet peanut butter treat.

This recipe is designed to deliver maximum flavor with minimal fuss. You’ll get a cake that’s moist and fluffy, paired with frosting that’s sweet but not overpowering, with just the right peanut butter punch.

Ingredients

Cake:

• 2 cups all-purpose flour
• 1 ½ tsp baking powder
• ½ tsp baking soda
• ½ tsp salt
• 1 cup unsalted butter, softened
• 1 cup creamy peanut butter
• 2 cups granulated sugar
• 4 large eggs
• 1 tsp vanilla extract
• 1 cup milk

Frosting:

• 1 cup unsalted butter, softened
• 1 cup creamy peanut butter
• 4 cups powdered sugar
• 2–3 tbsp heavy cream or milk
• 1 tsp vanilla extract
• Optional: chopped peanuts for garnish

Instructions

1. Preheat oven: to 350°F (175°C). Grease and flour a 9×13-inch baking pan.
2. Mix dry ingredients: In a medium bowl, whisk together flour, baking powder, baking soda, and salt.
3. Cream butter and peanut butter: In a large bowl, beat butter, peanut butter, and sugar until light and fluffy. Add eggs one at a time, mixing well after each. Stir in vanilla extract.
4. Combine ingredients: Gradually add dry ingredients alternating with milk, beginning and ending with dry ingredients. Mix until smooth.
5. Bake: Pour batter into prepared pan and bake 30–35 minutes, or until a toothpick inserted into the center comes out clean. Cool completely.
6. Make frosting: Beat butter and peanut butter together until creamy. Gradually add powdered sugar, mixing well. Add vanilla and 2–3 tbsp milk to reach desired spreading consistency.
7. Frost cake: Spread frosting evenly over cooled cake. Garnish with chopped peanuts or chocolate drizzle if desired. Slice and serve.

Tips for the Perfect Peanut Butter Sheet Cake

• Room temperature ingredients: Ensure butter, eggs, and milk are at room temperature for smooth batter.
• Don’t overmix: Overmixing the batter can make the cake dense. Mix until just combined.
• Frosting texture: If frosting is too thick, add an extra teaspoon of milk at a time until it spreads easily.
• Storage: Store in an airtight container at room temperature for 2 days or refrigerate for up to 5 days.

Peanut Butter Sheet Cake with Fluffy Peanut Butter Frosting

Moist and fluffy peanut butter sheet cake topped with a light, airy peanut butter frosting. Perfect for birthdays, potlucks, and peanut butter lovers.

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 35 minutes mins

Total Time 55 minutes mins

Servings: 12 slices

Course: Dessert, Snack

Cuisine: American

Calories: 340

Ingredients Equipment Method Notes

Ingredients

  

Cake

• 2 cups all-purpose flour
• 1.5 tsp baking powder
• 0.5 tsp baking soda
• 0.5 tsp salt
• 1 cup unsalted butter softened
• 1 cup creamy peanut butter
• 2 cups granulated sugar
• 4 eggs large
• 1 tsp vanilla extract
• 1 cup milk

Frosting

• 1 cup unsalted butter softened
• 1 cup creamy peanut butter
• 4 cups powdered sugar
• 2-3 tbsp heavy cream or milk
• 1 tsp vanilla extract
• optional chopped peanuts for garnish

Equipment

• Mixing bowls
• 9×13 inch baking pan
• Hand mixer or stand mixer
• Spatula
• Measuring cups and spoons

Method

 

1. Preheat oven to 350°F (175°C). Grease and flour a 9×13-inch pan.
2. Whisk flour, baking powder, baking soda, and salt in a medium bowl.
3. Beat butter, peanut butter, and sugar until light and fluffy. Add eggs one at a time. Stir in vanilla.
4. Gradually add dry ingredients alternating with milk. Mix until smooth.
5. Pour batter into prepared pan and bake 30–35 minutes or until a toothpick comes out clean. Cool completely.
6. Beat butter and peanut butter for frosting until creamy. Gradually add powdered sugar, then vanilla and milk to desired consistency.
7. Spread frosting over cooled cake and garnish with chopped peanuts if desired. Slice and serve.

Notes

Store cake in an airtight container. Frosting can be made a day ahead for convenience.

Variations

1. Chocolate Swirl: Swirl melted chocolate into the batter before baking.
2. Crunchy Topping: Add crushed pretzels or toffee bits on top of the frosting.
3. Mini Cupcakes: Bake the batter in a cupcake tin for single-serve treats.
4. Peanut Butter & Jelly Twist: Add a layer of your favorite jelly between cake and frosting.

Serving Suggestions

• Serve with a glass of cold milk for a nostalgic treat.
• Pair with coffee or hot chocolate for an indulgent dessert experience.
• Perfect for birthday parties, school events, or potlucks.

Fun Fact

Peanut butter desserts have been a beloved American tradition since the early 20th century. This sheet cake takes inspiration from classic peanut butter cakes but simplifies the process with a fluffy, easy-to-spread frosting that’s perfect for any occasion.

Why You’ll Love This Recipe

• Easy & Quick: Minimal ingredients, straightforward instructions.
• Moist & Fluffy: Cake is perfectly tender without being dry.
• Rich Peanut Flavor: The frosting and cake deliver a double dose of peanut butter goodness.
• Family Favorite: Loved by kids and adults alike.