Chocolate Peanut Butter Cake

Amethyst · December 9, 2025, 11:56pm

Chocolate Peanut Butter Cake

Prep Time: 1 hour
Cook Time: 30 minutes
Total Time: 1 hour 30 minutes
Yield: 12

Ingredients:

For the chocolate cake:

4 ounces unsweetened chocolate, chopped
⅓ cup Dutch-process cocoa (35g)
½ cup hot water (4oz)
1 ¾ cups all-purpose flour (226g)
1 ½ teaspoons baking soda
1 teaspoon salt
1 cup buttermilk, full-fat fat well shaken (8oz)
¼ cup vegetable oil (2oz)
2 teaspoons vanilla extract
5 large eggs, room temperature
8 tablespoons unsalted butter, very soft (113g or 4oz)
1 cup granulated sugar divided (222g)
¾ cup brown sugar packed (170g)

For the peanut butter frosting:

1 cup unsalted butter softened (226g or 8oz)
1 cup smooth peanut butter like Jiff or Peter Pan (260g)
2 ½ cups powdered sugar (287g)
⅛ teaspoon salt
1 teaspoon vanilla extract
1 tablespoon heavy cream or milk as needed (±) for desired consistency

For the chocolate ganache (optional):

⅓ cup heavy cream
1 ½ tablespoons corn syrup
3 ounces semisweet chocolate, chopped or bittersweet
chopped dry-roasted salted peanuts for garnish

Directions:

To prepare the cake:

Preheat oven to 350°F. Adjust the oven rack to the middle position. Butter two 9-inch round cake pans with 2-inch high sides. Dust pans with flour and knock out any excess. Set aside.

In a medium heatproof bowl, combine the unsweetened chocolate, cocoa, and hot water. Set the bowl over a saucepan with 1 inch of simmering water. Do not let the bowl touch the water.

Stir with a spatula until completely melted, about 3 minutes. Add ½ cup of granulated sugar and stir until the mixture is thick and glossy. Remove from the hot water and set aside to cool.

In a separate medium bowl, whisk together the flour, baking soda, and salt; set aside. In a 2-cup measuring cup with a spout, whisk together the buttermilk, vegetable oil, and vanilla; set aside.

In the bowl of a stand mixer fitted with the whisk attachment, whisk the eggs and medium-low speed until combined. Add the remaining ½ cup of granulated sugar and all the brown sugar. Turn the mixer speed to high and whisk until the mixture is thickened, lighter in color, and fluffy, about 3 to 4 minutes.

Replace the whisk with the paddle attachment. Add the cool chocolate mixture and blend until incorporated, scraping down the sides and bottom of the bowl as needed with a rubber spatula. Add the softened butter one tablespoon at a time, mixing well after each addition before adding the next.

Next, add one-third of the flour mixture, then half the buttermilk, blending well after each addition. Repeat, adding half the remaining flour, then all remaining buttermilk, and finally add the last of the flour mixture. Scrape down the sides and bottom of the bowl and fold a few times with a spatula to ensure all flour is incorporated. Divide the batter evenly between the prepared cake pans.

Bake the cakes until a toothpick inserted in the center comes out with no wet batter, about 28 to 35 minutes. Don’t over-bake! Moist crumbs are good. Cool the cakes in the pans for 15 minutes, then invert onto a wire cooling rack. Cool completely before icing.

To prepare the peanut butter frosting:

Beat the butter and peanut butter together until smooth. Sift in the powdered sugar and salt. Blend on low until combined. Scrape down the sides and bottom of the bowl and add the vanilla. Beat on medium until incorporated, then increase the speed to medium-high. Beat until light and fluffy, about 3 to 5 minutes. Add a tablespoon of cream as needed for the desired consistency.

Place one layer of cooled cake on a cake stand or serving platter. Spread 1 ½ cups of frosting over the cake layer. Top with the remaining cake round. Spread frosting on the sides and top of the cake. Refrigerate while preparing the ganache, if using.

To prepare the chocolate ganache:

Heat the cream and corn syrup in a small saucepan over medium heat until it comes to a simmer. Remove from the heat and add the chopped chocolate. Stir and cover with a lid. Set aside for 5 minutes. Whisk gently until smooth.

Spread the ganache on top of the cake, allowing any extra to decoratively drip down the sides. Sprinkle the ganache with chopped peanuts. Refrigerate to help set the ganache or leave it out at room temperature for an hour or until ready to serve.

Notes:

Store cake covered at room temperature for up to 3 days or refrigerate for longer storage. Allow to come to room temperature before serving.

Frosting recipe adapted from Cook’s Illustrated

Extra frosting:

If you’re not planning to use the chocolate ganache topping or prefer a thicker layer of frosting, feel free to make 1 and 1/2 times the frosting recipe.

This recipe can also be made into three 8-inch layers. However, it’s best to make extra frosting to ensure you have enough to cover all the layers.

Bake in your favorite pans:

This chocolate cake recipe can be baked in two 9-inch layers, as we’ve done here, or three 8-inch layers. For 8-inch layers, reduce the baking time to 15 to 20 minutes.

You can also make this into a sheet cake by pouring the batter into a buttered and floured 13×9-inch baking pan. Bake until a toothpick comes out with a few moist crumbs attached, about 30 minutes.

How to store Chocolate Peanut Butter Cake:

This cake is best served at room temperature. It can be stored in a covered container or cake carrier at room temperature for up to 3 days.

You can also refrigerate this cake for longer storage. Be sure to remove from the refrigerator at least 30-60 minutes before serving.

Freeze slices of cake in an airtight container for up to 3 months.

Nutritional Facts:

Recipe courtesy of Saving Room for Dessert.com