Start by preparing the mousse:break the eggs, separating the whites from the yolks, break the dark chocolate into pieces and melt it in a bain-marie over low heat. Add the butter in pieces and smooth the mixture. Add the yolks one by one, whisking constantly, then the rum.
Beat the egg whites until stiff, add the sugar and gently fold them into the chocolate mixture.
Prepare the sheets, divide the puff pastry into 3 equal parts, roll out one of the pieces into a large square 3 mm thick, cut out 6 rectangles of 10 cm by 5 cm. Place them on the oven tray moistened with a brush and leave to rest for 1 hour in the refrigerator.
Preheat the oven to th.7 (210°C).
After an hour, put in the oven and cook for 30 minutes, let the sheets cool on a wire rack.
Proceed in the same way with the other two pieces of dough.
Prepare the sauce:pour the cream into a saucepan, add the white chocolate in pieces and heat over low heat, when the chocolate has melted, smooth the mixture.
Remove the mousse from the refrigerator. On dessert plates, place the first 6 rectangles, garnish them with mousse using a spatula or piping bag, place 6 other rectangles on the mousse, garnish with the rest of the mousse, top with the Last 6 rectangles.
Decorate with dark and white chocolate shavings and surround with white chocolate sauce.
