Roughly chop the chocolate. Heat the cream, remove from the heat and melt the chocolate in it while stirring. Put the chocolate cream in a bowl and let it cool down for about 2 hours. Chill for about 30 minutes.
Place the sponge cake bases next to each other. Whip the chocolate cream with the whisk of the hand mixer until creamy. Spread each cake base with 1/3 chocolate cream and layer. Finally spread Maltesers on the cake.