This recipe is a paired down chocolate log recipe so we’re actually going to use ⅓ of a 10 by 15 pan to bake it in. To do this you need to cut a piece of tin foil that is 10 inches wide (or slightly more) by at least 3 inches. Fold it in half repeatedly until you get a piece of tin foil that is 10 inches wide and about the depth of the pan. Wedge your tin foil barrier into your pan so that you separate ⅓ of the pan from the other ⅔ .

You can prop the barrier up with a spare round or square cake pan filled with pie weights (or dried chickpeas, which I use instead of store bought pie weights). For an idea of what this should look like take a look at the photos in the post above.

Grease the ⅓ side of the pan with oil or butter and then line with parchment paper. The paper should be wide enough so that you have an overhang on the two long sides, this will make it easy to pull the cake out once it’s cooked.

Preheat the oven to 350 F.

Combine the chopped chocolate and water or coffee in a heat proof bowl and melt over a pan with simmering water (like a bain-marie) until the chocolate is about 80% melted. Remove from the heat and stir it so that the chocolate melts all the way. Let it cool while you prep the eggs.

Separate the eggs into two mixing bowls. Beat the yolks with an electric mixer until the color has lightened significantly. Add in the sugar and keep beating until you get a thick mixture that is very pale in color.

Stir the chocolate into the egg yolk mixture.

Beat the egg whites with the salt using a clean mixer (any residual egg yolk will make it impossible to beat the egg whites). Once they’ve reached a stiff peak consistency fold ⅓ of the whites into the chocolate mixture to loosen it. Fold the rest of the egg whites in.

Pour into your prepared pan and bake for 15 minutes or until the surface of the cake is dry.

Dust a clean kitchen towel with the cocoa powder. You need quite a thick layer so be generous with it.

Once the cake is ready remove it from the oven and let it cool for a minute before turning it out onto the kitchen towel. Carefully peel off the paper.

Fold the edge of the towel over the cake and then roll the cake up with the towel. Let the cake cool wrapped in the towel.

Make the hazelnut butter following the instructions from these cookies. If you have left over from making the cookies just let the spread come back to room temperature. You can also skip this step and just use the whipped cream filling.

Whip the cream until soft peaks form. Stir in the icing sugar and optional alcohol. Adjust flavor by adding more sugar or alcohol if you want.

Make the ganache (if you’re using it). Heat the cream in a bowl in the microwave until it’s just simmering. Stir in the chocolate chips and let sit for 5 minutes before stirring again to combine.

Unroll the cool cake and spread over the hazelnut butter (if using). Then spread a layer of whipped cream over the cake.

Reroll the cake using the towel to help you guide it.

Cover the rolled cake with the ganache and then refrigerate until ready to serve.