1. Line a 23cm spring form tin with baking parchment
2. Crush the digestive biscuits to crumbs and mix in the melted butter
3. Tip the mixture into the tin and press down into the base to create an even layer
4. Gently whisk the eggs and sugar
5. Whip the cream cheese and combine with the eggs and sugar
6. Melt the chocolate separately
7. Add the white chocolate to the cream cheese mixture
8. Pour into the tin
9. Marble the dark chocolate through the cream cheese without mixing. (Chefs top tip – a knife can be used to help marble the chocolate though). Bake at 140C for 1 hr 30 minutes and then allow to cool in the tin.