Chocolate Peanut Butter Mousse Cake
Slice into this chocolate peanut butter mousse cake to reveal two light and airy mousses swirled atop a fluffy chocolate sponge and below a rich chocolate ganache. I love a cake that is simple and unfussy on the outside and absolutely showstopping on the inside, and this cake is exactly that. It needs no decoration, but it still has that "wow factor" from the prominent peanut butter & chocolate flavors and gorgeous marbled effect. It's also a textural dream from the soft cake to the cloud-like mousse and to the creamy ganache. The overnight chill and zero decoration make it the perfect make-ahead dessert to bring to a party!
Ingredients
For the chocolate sponge:
- 56 g (2 oz) semisweet chocolate
- 50 g (¼ cup) neutral oil
- 132 g (⅔ cup) granulated sugar
- ¼ teaspoon salt
- 3 eggs, separated
- ½ teaspoon vanilla extract
- 40 g (⅓ cup) all-purpose flour
- 21 g (¼ cup) dutch process cocoa powder
For the chocolate & peanut butter mousses:
- 170 g (1 cup) semisweet chocolate
- 260 g (1 cup) thick & creamy peanut butter, such as Jif
- 340 g (1 ½ cups) whole milk
- 84 g + 540 g (¼ cup + 2 tbsp, 2 ¼ cups + 2 tbsp) heavy cream, divided
- 2 eggs
- 50 g (¼ cup) granulated sugar
- ½ teaspoon salt
For the chocolate ganache:
- 170 g (¾ cup) heavy cream
- 170 g (6 oz) semisweet chocolate
- 21 g (1.5) unsalted butter
Instructions
For the chocolate sponge:
- Preheat the oven to 350 degrees F. Line a 9" springform pan with parchment paper.
- In a small heat-proof bowl, combine the chocolate and oil. Place the bowl over a small pot of simmering water, and stir frequently until the chocolate has full melted. Set aside to cool.
- In a medium bowl, vigorously whisk the sugar, salt, egg yolks, and vanilla until the mixture is pale in color and drizzles off the whisk like a ribbon.
- Pour the cooled chocolate mixture into the egg yolk mixture and mix to combine.
- In a separate bowl, add the egg whites and use an electric hand mixer to beat until stiff peaks form.
- Use a rubber spatula to fold ⅓ of the egg whites into the yolk, chocolate mixture to loosen it up, then fold in the rest until fully combined.
- Sift the flour and cocoa powder on top of the batter, then gently fold it in until fully combined. Be careful not to deflate those egg whites!
- Pour the batter into the prepared pan. Bake the chocolate sponge for about 18-20 minutes or until a toothpick inserted comes out clean.
- Allow the cake to cool completely before adding the mousses. You can also place the cake in the fridge to cool down faster.
For the chocolate & peanut butter mousses:
- In two medium bowls, add the chocolate to one bowl and the peanut butter to the other. Set aside.
- In a small saucepan, bring the whole milk, 84 (¼ cup + 2 tbsp) heavy cream, eggs, sugar, and salt to just shy of a simmer (180 F).
- Pour the anglaise base through a fine mesh sieve over the chocolate, weighing the anglaise out to 180g. Do the same to the peanut butter. Mix both until smooth.
- In a separate large bowl, add the remaining 540g (2 ¼ cup + 2 tbsp) heavy cream and use an electric mixer to beat until stiff peaks form.
- Add half of the whipped cream to the chocolate mixture in two parts and gently fold with a rubber spatula until fully combined. Repeat with the other half and the peanut butter mixture.
- Once the cake is cool, use a knife to loosen the cake from the edges of the pan. Open the springform pan, then add a cake collar and close the pan again.
- Alternate adding the mousses to the cooled cake, then swirl them slightly with a knife, and smooth out the top with an offset spatula. Chill the cake for at least 6 hours or overnight.
For the chocolate ganache:
- In a small saucepan over low-medium heat, bring the heavy cream to a simmer, or about 190 degrees F.
- Add the chocolate and butter, then place the lid on top for one minute. Remove the lid, then stir with a rubber spatula until smooth.
- Pour the ganache over the chilled cake and spread into an even layer.
- Place the cake back in the fridge until the ganache is set (about 30 minutes), then remove from the springform pan, peel back the cake collar, and serve!
Notes
- Mix the cake batter very gently. Once you start folding in the egg whites and dry ingredients, be sure to use a rubber spatula and mix in a very gentle method through the middle and around the sides. This will ensure that all that air you just beat into the egg whites doesn't deflate! And this air is essential to the cake rising in the oven and baking up into a light & fluffy sponge.
- Add a cake collar before spreading the mousse on the cake. This will ensure a nice and neat edge on the mousse and will make it easier to remove it from the pan.
Nutrition Facts
Serving: 1slice | Calories: 420kcal | Carbohydrates: 32g | Protein: 9g | Fat: 30g | Saturated Fat: 13g | Polyunsaturated Fat: 5g | Monounsaturated Fat: 10g | Trans Fat: 0.1g | Cholesterol: 76mg | Sodium: 214mg | Potassium: 321mg | Fiber: 3g | Sugar: 24g | Vitamin A: 387IU | Vitamin C: 0.1mg | Calcium: 70mg | Iron: 2mg
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