Crush biscuits into a fine sandy texture, add melted butter and mix. Divide mixture between cups and press flat, set aside in fridge to set.
In a microwave safe bowl add chocolate and 100mls of cream, heat in short bursts in microwave making sure to stir periodically. Once completely combined, set aside to cool slightly.
Place 400mls of cream into a stand mixture and beat until stiffly whipped.
Poor chocolate mix into whipped cream and fold in gently until fully combined.
Divide mixture between cups and set back in fridge to seat for at least 2 hours.