- STEP 1
Preheat the oven to 170°C/gas mark 3.
- STEP 2
Melt the chocolate and 125g of sugar in a bain-marie (a bowl suspended over a pan of simmering water). Set aside to cool slightly.
- STEP 3
Meanwhile make the biscuit base by mixing together the crushed digestives, melted butter and sugar. Press into a 20cm spring-form tin.
- STEP 4
In a large bowl, beat the cream cheese, remaining caster sugar, soured cream, vanilla extract and eggs until well-mixed.
- STEP 5
Pour half the mixture into the bowl with the melted chocolate and mix in thoroughly.
- STEP 6
Spoon in alternate amounts of the plain vanilla mixture and the chocolate one onto the biscuit base. Bake for 50 minutes until firm, cool before serving.