Chocolate Fudge Peanut Butter Cake
- For the cake:
- 2 cups all-purpose flour
- 2 1/2 cups sugar
- 3/4 cup unsweetened cocoa powder, preferably Dutch process
- 2 tsp baking soda
- 1 tsp salt
- 1 cup neutral vegetable oil, such as canola, soybean or vegetable blend
- 1 cup sour cream
- 1 1/2 cups water
- 2 tbsp distilled white vinegar
- 1 tsp vanilla extract
- 2 eggs
- 2 cups creamy peanut butter
- 4 cups powdered sugar
- 1 cup plus 2 tbsp unsalted butter, at room temperature
- 1 tbsp plus 1 1/2 tsp pure vanilla extract
- 3/4 tsp Kosher salt
- 1/2 cup heavy whipping cream
- 8 oz semisweet chocolate, coarsely chopped
- 3 tbsp smooth peanut butter
- 2 tbsp light corn syrup
- 1/2 cup half-and-half
For the frosting:
For the chocolate-peanut butter ganache:
- To make the cake:
- Preheat the oven to 350 degrees F. Grease (no flour is needed here) three 8-inch round cake pans with butter or baking spray. Line the bottom of each pan with a round of parchment paper and lightly grease the paper.
- In a very large bowl, sift the flour, sugar, cocoa powder, baking soda, and salt. Whisk to combine them well. Add the oil and sour cream and whisk to blend. Gradually beat in the water – splashing may occur if you add it too quickly (trust me). Blend in the vinegar and vanilla. Whisk in the eggs and beat until well blended. Scrape down the sides and bottom of the bowl and be sure the batter is well-mixed and no flour bits remain. Divide among the 3 prepared cake pans – using a kitchen scale really helps to ensure the layers will be equal in size.
- Bake for 30 to 35 minutes on the same rack, if possible, without the cake pans touching each other, or until a cake tester or wooden toothpick inserted in the center comes out almost clean. Let cool in the pans for about 20 minutes. Invert onto wire racks, carefully peel off the paper liners, and let cool completely.
- In the bowl of a stand mixer fitted with the paddle attachment, place the peanut butter and butter. Sift the sugar into the bowl. Add the vanilla extract and salt. Starting on low and gradually increasing (to prevent the sugar from covering your kitchen) the speed to medium-high, beat the ingredients until light and fluffy, scraping the sides and bottom of the bowl as needed, about 3-4 minutes. Beat in the heavy whipping cream.
- Place one layer, flat side up, on a cake stand, cardboard cake round, or large serving plate. Spread 2/3 cup of the peanut butter frosting evenly over the top. Repeat with the next layer. Place the last layer on top and frost the top and sides of the cake with a scant amount of frosting to make a crumb coat to keep the crumbs from popping through the final frosting. You’ll need just enough to lightly cover the cake – there’s no need to be neat here. Let the cake chill for 15 to 30 minutes until firm, then use the remainder of the frosting to create a smooth final coating. Once the cake is fully frosted, chill the cake again and let it firm up before covering it with the ganache.
- In the in a medium bowl set over a saucepan of simmering water, combine the chocolate, peanut butter, and corn syrup. Cook, whisking often, until the chocolate is melted and the mixture is smooth. Remove from the heat and whisk in the half-and-half, beating until smooth. Use while still warm. (I put the ganache in the fridge for a very short time, just to help it firm up a bit before adding it to the cake. I didn't want it to be too "drippy".)
- Gently pour the ganache over the top of the cake, and using an offset spatula, spread it evenly over the top just to the edges so that it runs down the sides of the cake in long drips. Refrigerate, uncovered, for at least 30 minutes to allow the ganache to set completely. Take the cake out of the fridge about 1 hour before serving – it will be difficult to cut through the ganache if it is too cold.
To make the frosting:
To frost the cake:
To make the ganache:
To decorate with the ganache: