Blitz the biscuits to a fine crumb in a food processor, or bash in a bowl to a fine crumb
Mix in the melted butter, to a wet sand texture, and press into the base of an 8" springform cake tin
In a new bowl, dissolve the coffee in the boiling water and add the coffee liqueur, and leave to cool
In a new bowl, add the mascarpone, icing sugar, vanilla and coffee liqueur, and whip together until smooth
Add in the double cream and whip again until thick (alternatively, whip the cream separately and fold through)
Spread half of the cheesecake mix onto the biscuit base and smooth over
Dip the sponge fingers in the cooled coffee mix, and then add onto the cheesecake mix creating a layer
Add the second half of the cheesecake mix on top and smooth over.
Set in the fridge for 5-6 hours, or preferably overnight
Once set, remove from the tin carefully
Whip the cream, icing sugar and vanilla to soft peaks and then pipe onto the top of the cheesecake
Dust with cocoa powder and serve
