Crush biscuits finely and melt butter. Once butter cools, combine both together.
Line the bottom of a loose base tart tin with a baking sheet. For this recipe tart tin size has to be 22-24cm.
Add biscuit mix to the tin and press down with the back of a spoon including the sides of the tin. Put in fridge for an hour or in freezer for 10-15 minutes.
Start softening mascarpone with a whisker in a bowl together with the icing sugar and vanilla essence. Leave it on the side.
Start whipping 120ml of the cream straight from the fridge and gently fold it into the mascarpone mixture. Fold it gently with a spatula from bottom upwards.
Remove tart tin from fridge and pour in mascarpone mix. Put back in fridge and leave it for around 3-4hrs to set.
In the meantime start breaking cooking chocolate and put aside.
Heat the rest of cream (120ml) up until it reaches boiling and remove from heat. Add the chocolate in pieces and stir to melt. Leave aside to cool down completely.
When cake has been set in fridge and chocolate cooled down, pour over the chocolate and help with the back of a spoon to spread it evenly across whole surface. Put back in fridge for another hour before serving.