Chocolate Peanut Butter Mousse Cake

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.

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.

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!