Place a saucepan over low heat, pour in the milk and cream, add the chocolate chips and blend until the chocolate melts and the mixture becomes smooth and homogeneous.
Cut the biscuits into small pieces and mix them with 1/3 of the chocolate mixture. Transfer to the pan lined with baking paper or cling film.
Pour the remaining chocolate mixture over the biscuits and refrigerate for at least 3 hours.
Carefully unmold the cake and cut it into squares.
Arrange the biscuit squares on a serving plate and serve!
