1/2 cup all purpose flour
1/2 cup cocoa powder, plus more for dusting
6 eggs, separated
1 cup sugar
1/2 teaspoon sea salt
1 teaspoon vanilla extract
Peanut Butter Mousse:
1 pound 4 ounces (from 2 1/2 8 ounce packages) cream cheese, room temperature
2 cups / 500 grams creamy peanut butter
1/2 cup powdered sugar
1/4 cup heavy cream
1/4 teaspoon sea salt
8 ounces heavy cream
8 ounces bittersweet chocolate, chopped
Salted Peanut Caramel:
8 oz/ 1 cup sugar
6 oz/ 1/2 cup Lyle’s Golden Syrup or corn syrup
1/4 cup water
8 oz/ 1 cup heavy cream
2 oz/ 4 tablespoons butter, soft
1/2 vanilla bean, seeds removed (optional)
6 ounces roasted and salted peanuts
For the cake:
Preheat your oven to 350°F. Grease and line a 12x17-inch jelly roll pan with parchment paper. Grease the parchment paper. Set aside.
Sift together the flour and cocoa powder in a bowl then set aside. Then whisk to combine.
Add the egg yolks to the bowl of a stand mixer fitted with the whisk attachment. Beat on medium speed until frothy and just starting to shift from lemon yellow to butter yellow. Add 1/3 cup of the sugar in a slow and steady stream. Continue to beat until thick and pale yellow, about 4 to 5 minutes.
Add the whipped egg yolks to a large bowl then clean the stand mixer bowl and whisk. Wipe dry then add the egg whites.
Beat starting on low then gradually build up the speed so as not to shock the eggs. Once frothy add the salt. Continue to beat until soft peaks form then steadily stream in the remaining 2/3 cup sugar. Beat until stiff peaks form.
Fold the egg whites into the whipped yolks. Gingerly fold the dry ingredients into the whipped eggs. Continue to fold until no streaks remain.
Use an offset spatula to spread the batter into the prepared pan and bake for 10 to 12 minutes or until the cake slowly springs back when pressed.
Lay a piece of parchment paper, as large as the cake, on a clean flat surface. Dust it generously with cocoa powder. In one swift action invert the cake onto the parchment. Peel off the still warm cake’s parchment layer then dust the cake itself with another generous flurry of cocoa powder.
While the cake is warm and pliable gingerly roll it up with the parchment. Let the cake cool in this position. While the cake cools make the mousse or once cooled, wrap the cake tightly in plastic wrap then save the next steps for tomorrow.
For the mousse:
In a large bowl or in the bowl of a stand mixer fitted with the paddle attachment add the cream cheese and peanut butter. Beat until smooth. Stir in the powdered sugar, heavy cream and salt and mix until well combined.
This can be made up to 3 days in advance. Cover and refrigerate then bring to room temperature when ready to use.
For the ganache:
Add the cream to a small saucepan and bring to a rolling boil. Watch the pot carefully as cream tends to bubble up and over rather quickly. Add the chocolate to a large bowl then pour the hot cream over the chocolate. Let this sit for one minute then whisk to combine. Stir in the salt.
Let the ganache cool until it’s firm enough to easily spread on the cake, about 1 hour.
Ganache can be made up to 1 week in advance then rewarm gently in the microwave or in a saucepan on low heat.
For the caramel:
Combine the sugar, golden syrup and water in a large saucepan. Stir gently to combine then wash off the sides of the pan using water and your clean hands to feel if any sugar remains on the side. If stray bits of sugar fall into the caramel it can cause the caramel to crystallize so it’s important to make sure all the sugar is in the bottom of the pan mixed with the water.
Set the pan over high heat to bring the sugars to a rolling boil. Continue to cook until the caramel turns copper in color, about 7 to 10 minutes. Carefully add the cream, butter and vanilla bean, if using. The caramel will immediately seize but let it come back to a boil. Once the sugar is all melted stir in the peanuts.
Let the caramel cool before serving. This can be made up to three days in advance.
If the caramel is too stiff you can rewarm in a microwave or in a saucepan to serve. Store caramel in a sealable container.
To assemble the cake:
Carefully unroll the cake from the parchment paper. Add the mousse in an even layer then roll the cake again. Don’t worry about any cracking or tearing in the cake the ganache is there to cover all that up.
Cover the entire cake with plastic wrap tightly, like a giant piece of candy, then refrigerate for at least 1 hour.
Place the cake on your serving platter.
Spread the ganache all over the cake. Cut off the ends at an angle and arrange in a way that resembles a log. Use a fork to create bark-like stiping in the ganache.
Serve straightaway or cover and refrigerate if you’ve made the cake in advance. Allow the cake to come to room temperature before serving.
Serve with the salted peanut caramel.