Pre-heat oven to 180 °C/350°F/gas mark 4.

Blend the biscuits and melted butter in a processor, until paste like. Spread out the mixture flat in a greased baking tin; leave in the fridge for 15 minutes.

Combine the raisins and rum in a small pan and heat. Remove from the heat and let the raisins marinade as they cool.

To make the filling, place the cheese, sugar and salt in the large bowl of an electronic mixer. On a medium speed beat, until smooth. Scrape the sides of the bowl with a spatula and then turn the speed up to high, and continue beat until nice and creamy. Stop the machine and add some sour cream and vanilla and continue to beat until all the ingredients are well combined. Pour in the melted chocolate and beat together well.

Remove the bowl and fold in the rum and raisin mixture. Pour into the prepared spring form pan, tapping once or twice on a firm surface - to level the mixture. Set the pan in the centre of a slightly larger baking pan. Pour enough hot water into the larger pan to reach halfway up the sides of the spring form pan, but not above the foil.

Carefully place both pans in the oven and bake until the top is lightly golden and slightly firm in the centre - about an hour and 10 minutes. (The cake will become firm as it cools down) Remove the pans from the oven and carefully lift out the springform pans and place on a rack and let it cool completely. Refrigerate, uncovered, overnight.

To serve, dip a knife into warm water and run the knife around the inside of the spring form pan and remove the outer ring. To cut into slices, dip the knife into warm water as necessary.

For Shiny chocolate sauce:

Break the chocolate into squares and melt it with the butter in a bowl over a pan of hot water. Stir in the sugar and syrup until dissolved, then pour in the milk and continue to cook stirring often until the sauce thickens.

Per serving: 5702 Calories (kcal); 437g Total Fat; (69% calories from fat); 92g Protein; 339g Carbohydrate; 1707mg Cholesterol; 4040mg Sodium Food Exchanges: 0 Grain(Starch); 10 Lean Meat; 0 Vegetable; 0 Fruit; 82 Fat; 19 1/2 Other Carbohydrates