Peanut Butter Fudge Cake
This peanut butter fudge cake is made with tender and moist chocolate cake layers that are filled with thick layers of milk chocolate and peanut butter ganache. It's a rich, perfectly decadent dessert that will have you going back for more.
Servings: 24 servings
Calories: 584kcal
Equipment
- Scale (optional)
Ingredients
Milk Chocolate Ganache
- 1 cup heavy whipping cream 240g
- 4 cups milk chocolate chips 720g
- 1/2 cup (1 stick) unsalted butter, room temperature 113g
- 1/4 cup light corn syrup - optional 80g
- 1/2 tsp fine salt 3g
Peanut Butter Ganache
- 2 cups finely chopped white chocolate or high-quality white chocolate chips 350g
- 1 cup creamy, shelf-stable peanut butter 250g
- 1 1/3 cups heavy whipping cream 320g
Chocolate Cake Layers
- 2 cups all-purpose flour 260g
- 2 cups granulated sugar 400g
- 3/4 cup unsweetened cocoa powder, sifted 75g
- 2 tsp baking powder 8g
- 1 1/2 tsp baking soda 9g
- 1 tsp instant coffee or espresso, optional
- 1 tsp fine salt 6g
- 1 cup water, warm 240g
- 1 cup buttermilk, room temperature 240g
- 1/2 cup vegetable or canola oil 110g
- 2 large eggs, room temperature 112g
- 1 tsp vanilla extract or vanilla bean paste 4g
Decorations (optional)
- 1/4 cup peanut butter, melted 64g
- 2 Tbsp chopped peanuts 18g
- 1 tsp flaky sea salt
Instructions
Milk Chocolate Ganache (for the filling & frosting)
- Heat 1 cup of heavy cream in a large, heatproof bowl in the microwave for 45 seconds, until it just begins to bubble and steam. If you don’t have a microwave, heat the cream in a small saucepan over medium heat until it just begins to steam and bubble.
- Gently pour 4 cups of milk chocolate chips into the heavy cream. Make sure the chips are fully covered with cream. Let the mixture sit for 1 minute. If you want to use dark (60-65% cocoa) chocolate chips, use 2 2/3 cups (480g) and 2 cups of heavy cream.
- Stir slowly until the cream and chocolate combine and the mixture is smooth. If any bits of chocolate aren't fully melted, heat the mixture again for 10 seconds and stir until smooth.
- Then mix in 1/2 cup (1 stick) of room-temperature unsalted butter, 1/4 cup of corn syrup (optional), and 1/2 tsp of fine salt until combined.
- Pour the mixture into a shallow, wide tray to help it cool faster, then cover it with plastic wrap to prevent the ganache from forming a skin. Set aside to let it cool to room temperature.
Peanut Butter Ganache (for the filling & frosting)
- Place 2 cups of white chocolate and 1 cup of peanut butter in a large bowl and set aside.
- Pour 1 1/3 cups of heavy cream into a heat-proof bowl and heat in 15-second intervals in the microwave until it just begins to bubble (this usually takes me 45-60 seconds). If you don't have a microwave, heat the cream over medium-high heat in a saucepan until it just starts to bubble.
- Pour the heavy cream over the white chocolate and peanut butter. Make sure all the white chocolate is submerged beneath the cream. Let the mixture sit for a couple of minutes.
- Use an immersion blender or a spoon to stir the ganache and combine the ingredients until the mixture is smooth. If you don't have an immersion blender, stir the mixture until it is fully smooth and no bits of unmelted white chocolate remain.
- Pour the mixture into a shallow, wide tray to help it cool faster, then cover it with plastic wrap to prevent the ganache from forming a skin. Set aside to let it cool to room temperature.
Chocolate Cake Layers
- Preheat oven to 350°F/175°C. Line three 8-inch cake pans with parchment paper rounds and spray the sides with nonstick baking spray. Set aside.
- Sift or whisk together 2 cups flour, 2 cups granulated sugar, 3/4 cup unsweetened cocoa powder, 2 tsp baking powder, 1 1/2 tsp baking soda, 1 tsp fine salt, and 1 tsp instant espresso or coffee (optional) in a large bowl. Set aside.
- In a separate, large bowl, add 1 cup warm water, 1 cup buttermilk, 1/2 cup oil, 2 eggs, and 1 tsp vanilla and whisk together until fully incorporated.
- Whisk the dry ingredients into the wet ingredients until they're just combined, and the batter is smooth.
- Pour the batter evenly (about 475g per pan if you're making 3 layers) between the 3 cake pans. Bake for 24-26 minutes or until a toothpick comes out with a few moist crumbs.
- Let the pans cool for 10 minutes, then run a small offset spatula around the perimeter of the pan to separate the cake from the pan.
- Place the cake pans into the freezer for 30 minutes to accelerate the cooling process. This helps lock in the steam and makes the layers extra moist. If you don't have room in the freezer, place the cake pans on a wire rack and let them cool fully before removing them.
- Once the layers are fully cooled, carefully flip the pans and remove the layers. These cake layers bake up pretty flat, so leveling them is optional, but I like to level them with a serrated knife to make the cake easier to fill and frost.
- If you make these cake layers in advance, let them thaw for about 15 minutes before making the cake. The cake layers should still be slightly cold to the touch, which will make it easier to assemble the cake.
Peanut Butter Fudge Cake Assembly
- Place the first cake layer on a greaseproof cake board or large flat plate, using a small dab of chocolate ganache to keep it in place.
- Spread about 1 1/4 cups (325g) of room-temperature chocolate ganache on the first cake layer, then top this with about 1 1/4 cups (325g) of the peanut butter ganache. Try to keep the filling relatively even so the next cake layer sits flat.
- Add the second cake layer, then chill the cake in the freezer for 10 minutes or the fridge for 20 minutes. Top the second layer with the same amount of chocolate and peanut butter ganache. Place the final cake layer upside down on top to make it easier to frost and minimize crumbing. Then chill the cake one more time for about 15 minutes in the freezer or 30 minutes in the fridge, or until the filling is firm.
- Whip the remaining room-temperature chocolate and peanut butter ganache together with a hand mixer or stand mixer on a high speed for 1-2 minutes, or until the mixture becomes lighter in color and increases in volume.
- Then cover the cake in a thick layer of whipped chocolate peanut butter ganache. Use a large offset spatula or the back of a spoon to create a textured look around the cake. Finish the cake with a ring of melted peanut butter, chopped peanuts, and sea salt on top, then dig in!
Notes
I highly recommend making your cake layers in advance and freezing them. It breaks the process up and makes it more approachable.
Both ganaches can be made ahead of time and stored in airtight containers in the fridge for up to a week or in the freezer for up to 3 months. Let them sit at room temperature for a few hours to bring them back to the proper consistency before assembling the cake.
A frosted cake can last in the fridge for up to a week, or in the freezer for up to a month. The whipped ganache locks in all the moisture, keeping the cake fresh and delicious!
Let the cake sit at room temperature before serving so the ganache has time to soften.
Nutrition
Serving: 1 | Calories: 584kcal | Carbohydrates: 61g | Protein: 7g | Fat: 37g | Saturated Fat: 18g | Polyunsaturated Fat: 4g | Monounsaturated Fat: 11g | Trans Fat: 0.2g | Cholesterol: 54mg | Sodium: 365mg | Potassium: 290mg | Fiber: 2g | Sugar: 48g | Vitamin A: 499IU | Vitamin C: 0.2mg | Calcium: 113mg | Iron: 1mg