Use a small chefs' ring to stamp out a circle of the Madeira cake. Discard the trimmings but keep the circle of cake in the ring.
Whisk the cream in a bowl until form soft peaks when the whisk is removed, then whisk in the mascarpone and sugar.
Stir in the lemon zest and juice and fold in the chopped apricots.
Spoon this mixture into the ring on top of the Madeira cake and smooth the top with a palette knifel.
Chill in the fridge until set.
Remove the ring by heating the outside with a blow torch, and arrange the raspberries on top.
Place the apricot syrup and tinned apricot halves in a food processor and blend to a purée.
Serve the cheesecake with the purée spooned around the side, garnished with a mint sprig.
