Divide crushed biscuits between six nice glasses or ramekins.
Beat cream cheese and sugar with an electric mixer until creamy. Beat in lemon zest and juice, then mascarpone. Divide cheesecake mixture evenly between the glasses. Chill.
Drain cherries from syrup and set cherries aside. In a saucepan, combine syrup with the cornflour mixture. Place over medium heat, bring to the boil and stir constantly 2-3 minutes until thickened. Place the syrup in a bowl, stir in cherries and refrigerate.
Just before serving, spoon some of the cherry mixture over the cheesecake.