Preheat the oven to 200ºC / fan oven 18OºC / gas mark 6. Grease a 20cm / 8 in spring form cake
pan and line with baking paper. Place the crushed biscuits and butter in a bowl and mix until well
combined. Transfer to the cake pan and press down well into the base to form a crust. Bake for just
7 minutes, then leave to cool.
Put the raisins or sultanas and lemon juice in a small pan and simmer gently for 5 minutes.
Drain well and set aside. In a large bowl, beat together the mascarpone and sugar until smooth.
Stir the egg yolks into the mascarpone with the lemon zest, cornflour, sour cream and fruit.
Pour the mixture into the prepared cake pan and bake for 45-50 minutes until golden. Allow to
cool completely, then remove from the cake pan.