100 g unsalted butter melted plus extra for greasing
200 g cream-filled chocolate sandwich biscuits
For the layers
1 litre Carte D'Or chocolate ice cream slightly softened
1 litre Carte D'Or coffee ice cream slightly softened
1 litre Carte D'Or vanilla ice cream slightly softened
For the topping
200 g dark chocolate
chocolate shards optional
chocolate truffles optional
Lightly grease a 15cm deep cake ring and line with baking parchment. Put onto a baking tray also lined with baking parchment. In a food processor, pulse the biscuits until finely crushed. Alternatively, put the biscuits in a bowl and break up by bashing with a rolling pin. Add butter and pulse/mix to combine. Press into the base of a prepared tin and smooth with the back of a spoon.
Spoon the softened chocolate ice cream over the biscuit base, and level with a spatula. Freeze for 2hr, or until firm. When firm, spoon over the softened coffee ice cream. Level with a spatula and freeze for 2hr, or until firm. When firm, spoon over the final layer of softened vanilla ice cream and level with a spatula. Cover the cake ring/tin with clingfilm and freeze for at least 4hr or, ideally, overnight, until frozen solid.
When ready to serve, make the chocolate topping. Melt chocolate in a bowl over a pan of barely simmering water. Remove the cake from the freezer. Leaving the ring on to give a neat finish, pour the melted chocolate on top of the cake and quickly spread with a palette knife into a smooth layer. Once the chocolate has started to harden, carefully remove the cake ring and peel off the greaseproof paper. Transfer to a serving plate or cake stand. Top the ice cream cake with a selection of chocolate shards, and white and milk chocolate truffles to serve, if you like.