Preheat oven to 180°C/350°F. Grease a 1.5-litre (6-cup) shallow ovenproof dish.
Sift flour and cocoa into a large bowl; stir in caster sugar, milk, egg, syrup and half the butter. Spread mixture into dish.
Stir brown sugar, coffee granules and the water in a medium heatproof jug until sugar is dissolved. Stir in marsala, cream and remaining butter. Slowly pour coffee mixture over the back of a spoon, over pudding batter.
Bake pudding 40 minutes or until firm in the centre. Stand 5 minutes.
Meanwhile, make mascarpone cream; beat mascarpone, cream and sifted icing sugar in a small bowl with an electric mixer until soft peaks form.
Dust pudding with extra cocoa; serve with mascarpone cream.