Preparation

• 1
  Preheat the oven to 170 degrees or 150 degrees fan oven.
• 2
  Grease the bottom of a 20cm loose bottomed circular cake tin and line with baking parchment. Wrap the outside of the whole cake tin with a double layer of tinfoil.
• 3
  Break up then crush the chocolate digestive biscuits and place them in a bowl. Cut the butter into pieces, melt it and then mix it well with the crushed biscuits.
• 4
  Tip into the bottom of the tin and then press down in a thin layer to cover the base of the tin. Bake for just 10 minutes - it will still feel soft but firm up when cooled - and leave to cool on a wire rack.
• 5
  In a large bowl, combine the cream cheese and the sugar until really smooth.
• 6
  Break the chocolate into small pieces and melt in a pyrex bowl over, but not touching, simmering water in a saucepan. Gradually pour it into the cheese and sugar mixture and stir well until combined. Sprinkle in the cocoa and stir in well too.
• 7
  Whisk the eggs together in a separate bowl and then gradually add to the mixture, beating in well as you do so. until everything is really well combined. Pour the mixture into the prepared tin.
• 8
  Place the cheesecake tin into a slightly larger roasting tin and pour 2-3 centimetres of boiling water into the larger tin. Bake for 60-65 minutes, or until the middle is set.
• 9
  Take off the foil, cool on a wire rack for 10 minutes and then quickly run a knife around the edge of the cheesecake. Chill overnight, or at least for several hours, once it has cooled for long enough to be put in the fridge.
• 10
  Carefully remove the chilled cheesecake from the tin and make the topping.
• 11
  Chop the chocolate into small pieces and place in a bowl. In a small saucepan, gently heat the cream until it is just about to boil, then pour it over the chocolate, stirring as you do so. Whisk as it cools until smooth and the desired consistency.
• 12
  Starting from the centre, spread the topping onto the cheesecake until it covers smoothly almost to the edge. Chill again for an hour or so, to set the topping before serving.