Whisk the jam, 75ml Marsala and the orange juice together. Set aside.
Place the mascarpone cheese and 2 tbsp Marsala in a large bowl. Fold just to blend and set aside.
Beat the cream, sugar, vanilla and the remaining 2 tbsp Marsala in another large bowl until soft peaks form.
Stir a quarter of the whipped cream mixture into the mascarpone mixture to loosen it, then gently fold in the remaining whipped cream.
Spread some of the jam mixture in the bottom of a 32cm x 22cm x 12cm serving dish (or you can use individual glasses). Arrange enough savoiardi over the jam mixture to cover the bottom of the dish. Spoon more of the jam mixture over the savoiardi, then spread some of the mascarpone mixture over. Arrange some raspberries over the mascarpone mixture.
Repeat the layering with the remaining savoiardi, jam mixture, mascarpone mixture and raspberries. Cover with cling film and chill for at least 8 hours or overnight. Arrange any leftover raspberries over the tiramisù and serve.