Preheat the oven to 200C/400F/Gas Mark 6.
Line the base 25 x 30 cm baking tray or Swiss roll pan and sides with some parchment paper.
Melt the chocolate in a heatproof bowl over a saucepan half filled with water (ensuring the water does not touch the base of the bowl). Stir until smooth.
In a separate bowl beat the eggs and sugar until light and creamy. Fold in the water, then the chocolate mixture.
Sift the self-rising flour and ground almond into the eggs and fold until smooth. Pour the mixture into the lined baking tray and bake for 10 minutes.
Place a layer of parchment paper larger than the baking tray onto a flat surface. Invert the cake onto the parchment paper and trim any crispy edges.
Meanwhile, to prepare the filling beat the mascarpone cream, cream and vanilla extract into a bowl and beat until smooth. Fold in the brandy and pudding crumbs. Spread the cream mixture on the sponge. To make the sauce, pour the cream into a saucepan and bring to the boil, remove from the heat and add the chocolate pieces, stir until smooth. Add a tablespoon of water and stir to combine.
Starting with the long side closest to you, and using the paper to help, roll up the cake. Place on a serving platter and pour over the chocolate sauce, top with some chocolate shavings.
Store in the fridge until required.