For the cheesecake base, place the biscuits, walnuts and butter into a food processor and blend until the mixture resembles breadcrumbs. Spoon into a 6cm/2½in metal chefs' ring on a well-greased baking sheet and flatten down with the back of a spoon.
For the cheesecake filling, place the mascarpone and whipped cream into a bowl and fold in the lemon juice and icing sugar. Spoon onto the biscuit base. Slice the cherries in half and arrange on top of the cream. Chill in the fridge for ten minutes.
When ready to serve, spoon six tablespoons of cherry syrup into a pan and reduce over a high heat until it reaches a thick syrup consistency.
Remove the cheesecake from the fridge, place on a plate and remove the metal ring. Drizzle the hot cherry sauce around the cheesecake and serve.