Place the sponge fingers into the cooled coffee and leave. Melt 25 grams of the butter over a low heat until melted. Crush the biscuits into a powdery consistency. Grease a cake tin with the other 5 grams of butter, mix the biscuits and melted butter and press into cake tin, refrigerate whilst you whisk the sugar, cheese and the double cream until thick. Mix the 1 tablespoon of the coffee granules and 1 tablespoon of hot water until liquidised, and add to the cream and cheese mixture. Take you sponge fingers. Drain the excess coffee and mash the fingers, when mashed layer on top of the biscuit base, add the cream and cheese mixture and smooth over the base. Grate the chocolate on to until the cream and cheese filling is covered. Refrigerate for 30 minutes and serve.