A rich, moist peanut butter cake topped with creamy peanut butter frosting — perfect for peanut butter lovers!

Why You’ll Love This Recipe

Moist and tender cake infused with peanut butter flavor.
Rich, creamy frosting that’s smooth and indulgent.
Simple sheet cake format is perfect for gatherings or birthdays.
Easy to make with everyday ingredients.
Pairs beautifully with chocolate drizzle or chopped peanuts for extra texture.

Ingredients

For the Cake:

• 2 cups all-purpose flour

• 1 1/2 teaspoons baking powder

• 1/2 teaspoon baking soda

• 1/2 teaspoon salt

• 1 cup unsalted butter, softened

• 1 cup granulated sugar

• 1 cup brown sugar, packed

• 3 large eggs

• 1 cup buttermilk

• 1/2 cup creamy peanut butter

• 1 teaspoon vanilla extract

For the Frosting:

• 1/2 cup unsalted butter, softened

• 1 cup creamy peanut butter

• 3 cups powdered sugar

• 1/4 cup heavy cream (more if needed)

• 1 teaspoon vanilla extract

Prep Time: 20 minutes
Cook Time: 35 minutes
Total Time: 55 minutes
Yield: 12 servings

Directions

Step 1: Preheat Oven

Preheat oven to 350°F (175°C) and grease a 9×13-inch baking pan.

Step 2: Mix Dry Ingredients

Whisk together flour, baking powder, baking soda, and salt.

Step 3: Cream Butter and Sugars

Beat butter, granulated sugar, and brown sugar until light and fluffy.

Step 4: Add Eggs

Add eggs one at a time, beating after each addition.

Step 5: Add Peanut Butter and Vanilla

Mix in peanut butter and vanilla until combined.

Step 6: Combine Wet and Dry

Alternate adding flour mixture and buttermilk, starting and ending with flour.

Step 7: Bake Cake

Pour batter into pan, smooth the top, and bake 30–35 minutes or until a toothpick comes out clean. Cool completely before frosting.

Step 8: Make Frosting

Beat butter and peanut butter until smooth. Gradually add powdered sugar, alternating with heavy cream, until creamy. Stir in vanilla.

Step 9: Frost Cake

Spread frosting evenly over cooled cake.

Tips & Variations

• Add a sprinkle of chopped peanuts on top for extra crunch.

• Drizzle melted chocolate over frosting for a peanut butter-chocolate combo.

• For a lighter frosting, reduce powdered sugar slightly or add more cream.

• Store leftovers in an airtight container at room temperature for 2–3 days or in the fridge for up to a week.

Frequently Asked Questions

Can I use natural peanut butter?
Yes, but the frosting may be slightly thinner. Chill before spreading if needed.

Can I make this cake ahead of time?
Yes, bake the cake and store unfrosted for up to 2 days. Frost just before serving.

Can I freeze this cake?
Yes, bake and cool completely, wrap tightly, and freeze for up to 2 months. Thaw overnight in the fridge before frosting.

Can I use milk instead of buttermilk?
Yes, but add 1 tablespoon of lemon juice or vinegar per cup of milk to mimic buttermilk acidity.

Final Thoughts

This Peanut Butter Sheet Cake is a dream for peanut butter fans — moist, rich, and perfectly sweet. The creamy frosting makes every bite indulgent, and it’s versatile enough to dress up with chocolate, nuts, or drizzle. Perfect for celebrations or simply treating yourself!