Description
This rustic Peanut Butter Fudge Cake features three layers of moist dark chocolate cake—achieved using buttermilk and hot coffee—sandwiched between a rich, salty peanut butter Swiss-style buttercream. It is layered with a glossy, fudgy chocolate ganache filling and topping. The balance of intense chocolate and creamy peanut butter makes this an honest, celebratory dessert.
Ingredients
- All-purpose flour
- Granulated sugar
- Dutch-processed cocoa powder
- Baking soda
- Baking powder
- Salt
- Large eggs
- Vanilla extract
- Buttermilk
- Vegetable oil
- Hot brewed coffee
- Semi-sweet chocolate (for ganache)
- Unsalted butter (for ganache)
- Heavy cream
- Creamy peanut butter
- Egg whites (for buttercream)
- Softened salted butter (for buttercream)
Instructions
- Start by whisking together your dry ingredients: the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Once they are evenly combined, add the eggs, vanilla, buttermilk, and oil. Stir this until it is just combined. Finally, pour in the hot coffee and stir quickly. The batter for this Peanut Butter Fudge Cake will be quite thin, but that is exactly what you want for a moist, tender crumb. Pour it into a sheet pan and bake at 350 F until a toothpick comes out clean, then let it cool completely.
- While the cake cools, prepare the ganache by placing your chocolate, butter, and vanilla in a bowl. In a small pan, heat the heavy cream and sugar until it is hot but not yet boiling. Pour this hot mixture over the chocolate and let it sit for a minute before stirring until it is perfectly smooth. Place this in the fridge to cool until it is firm enough to hold its shape; this usually takes about an hour.
- This is a Swiss-style buttercream that starts by whisking egg whites and sugar over a simmering water bath. Make sure the sugar is fully dissolved before moving the bowl to your stand mixer. Whisk on high until you have stiff, glossy peaks. Once the bowl feels cool to the touch, add your softened butter one tablespoon at a time. Finally, fold in the peanut butter until the frosting is light, airy, and full of flavor.
- To assemble the Peanut Butter Fudge Cake, cut your sheet cake into three even rectangles. Place the first layer down and spread a thin layer of ganache on top. I like to pipe a small border of ganache around the edge to keep the peanut butter frosting tucked inside. Spread half of the peanut butter buttercream over the ganache, then repeat with the second layer. Top the final layer with a smooth coating of ganache. Trim the edges for a clean, rustic look that shows off those beautiful interior stripes.
Notes
For the cleanest slice when assembling the cake, chill the baked and cooled cake layers for about 15 minutes before cutting them into rectangles. To ensure the buttercream remains stable, always make sure the bowl of whipped egg whites is completely cool to the touch before introducing the butter. This cake is best served at room temperature, allowing the ganache to soften slightly. Store any leftovers in an airtight container at room temperature for up to three days, or in the refrigerator for up to one week.
- Prep Time: 1 hour 30 mins
- Cook Time: 35 mins
- Category: Dessert
- Method: Baking
- Cuisine: American