Preheat the oven to 300°F and prepare the chocolate meringue. Combine the egg whites and a pinch of baking powder and beat until foamy. While whisking, add the first batch of powdered sugar. Sift the cocoa powder and the second batch of powdered sugar into the foamy egg white mixture. Carefully fold the cocoa powder and powdered sugar into the foamy mixture with a spatula. Spoon a little more than half of the chocolate meringue mixture into a piping bag.
Line a sheet pan with parchment paper and pipe 3 spirals onto the paper.
Line another sheet pan with parchment paper and pipe the rest of the meringue mass in long strips onto the paper. Put both pans in the oven and cook for 60 minutes, or until the meringue is crisp. Allow the meringue to cool down to room temperature.
Brush the meringue sticks with maple syrup and sprinkle ground cinnamon on top. Heat the blade of a knife and lightly press it down in intervals on the meringue sticks to create a tree bark look.
To prepare the chocolate mousse, first boil the heavy cream and finely chopped mint leaves over medium heat and pour the mixture through a sieve into a bowl with the dark chocolate and mix well. Allow the mixture to cool a little and then add the softened butter and use a hand mixer to combine everything. In another mixing bowl, whip the second batch of heavy cream until nice and fluffy and then gently fold the homemade whipped cream into the chocolate mixture. Spoon the chocolate mousse into a piping bag and set aside for now.
For the homemade raspberry jam, add the sugar and raspberries to a pot and cook over high heat for about 5 minutes. Crush the raspberries with a fork and let the jam cook over medium heat until it starts to thicken. Add 1 tablespoon of lemon juice and mix well. The jam should be smooth and spreadable. Now allow it to cool. Then place the first chocolate meringue spiral on a plate and spread a layer of raspberry jam over it.
Pipe a layer of chocolate mousse over the jam in a spiral shape.
Place the second chocolate meringue spiral on top and cover this one with a layer of raspberry jam and chocolate mousse as well. Repeat this process with the final chocolate meringue spiral. Then cover the entire cake with the rest of the chocolate mousse.
Break the meringue sticks and chocolate curls apart into shorter pieces and use them to decorate the entire cake. Garnish the cake with fresh berries and mint leaves.
