Peanut Butter Cake

A frosted sheet cake sprinkled with Reese's Pieces and cut into generous squares.

5 from 4 votes

Yield: 15 servings

Peanut Butter Cake is moist, fluffy, and packed with peanut butter flavor. The light, creamy frosting is also made with plenty of peanut butter, for a sweet and salty dessert everyone will adore.

Prep Time20

Cook Time30

Additional Time3

Total Time20

Ingredients

For the Peanut Butter Cake:

1 ½ cups all-purpose flour
1 teaspoon baking powder
¾ teaspoon baking soda
¼ teaspoon salt
½ cup (1 stick) unsalted butter, softened
1 tablespoon vegetable oil
1 ½ cup granulated sugar
½ cup creamy peanut butter
1 tablespoon vanilla extract
2 large eggs, room temperature
1 ¼ cups buttermilk, room temperature

For the Frosting:

½ cup (1 stick) unsalted butter, room temperature
¾ cup creamy peanut butter
1 teaspoon vanilla extract
¼ teaspoon salt
1 cup powdered sugar, sifted
1 to 2 tablespoons milk
1 cup Reese’s Pieces, optional, for topping

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Instructions

Preheat oven to 350°F. Spray a 9x13 inch baking dish with nonstick spray, and set aside.
In a medium bowl, combine the flour, baking powder, baking soda, and salt. Mix with a fork or a whisk, and set aside.
In a separate mixing bowl, combine the softened butter, vegetable oil, and granulated sugar. Starting on low, gradually increase the speed to medium-high, and mix for 2 - 3 minutes, until well-combined.
Turn the mixer to low. Add the peanut butter and vanilla extract, mixing until thoroughly incorporated. Next, add the eggs one at a time, mixing well between each addition. Gradually add the buttermilk, beating until well-combined.
Add the dry ingredients to the bowl, and mix until just combined and no more dry flour is seen. Be careful not to overmix. Pour the batter into the prepared baking dish.
Bake for 28 - 32 minutes, or until a toothpick inserted into the middle of the cake comes out clean. Once the cake is done baking, remove from the oven and allow to fully cool before frosting.

Frosting

To make the frosting, use a clean mixing bowl and hand mixer to cream the butter, peanut butter, vanilla extract, and salt together.
Add half the powdered sugar to the mixture. Add one tablespoon of milk, and combine. Add the rest of the powdered sugar. Gradually increase the speed of the mixer from low to high. Mix the frosting together for 2 - 3 minutes until light and fluffy. If icing is too thick, you can add the remaining 1 tablespoon of milk.
Spread the frosting over the fully cooled cake, and sprinkle Reese’s Pieces over the top (if desired). Serve immediately, or store in an airtight container for up to 3 days.

Video

Notes

Storage:

Fridge: Store this cake at room temperature, covered or in an airtight container. It will keep for up to three days.

Freezer: I recommend placing it in a covered container in the freezer for about one hour, to help the frosting firm up. Then wrap the cake tightly in a layer of plastic wrap, followed by a layer of foil. Mark with the date, and freeze for up to three months. Done! To serve, just let the cake thaw to room temperature-ish.

Nutrition

Serving: 1 slice, Calories: 497kcal, Carbohydrates: 53g, Protein: 8g, Fat: 29g, Saturated Fat: 13g, Polyunsaturated Fat: 4g, Monounsaturated Fat: 9g, Trans Fat: 1g, Cholesterol: 60mg, Sodium: 294mg, Potassium: 177mg, Fiber: 2g, Sugar: 40g, Vitamin A: 492IU, Vitamin C: 0.1mg, Calcium: 76mg, Iron: 1mg