In a bowl, whisk jam, 3 cups of orange liqueur, and orange juice. Place mascarpone cheese and 2 tablespoons of orange liqueur in a large bowl. Fold just to blend. Using an electric mixer, beat whipping cream, sugar, vanilla, and remaining 2 cups of orange liqueur in another large bowl to soft peaks. Stir 1/4 of whipped cream mixture into the mascarpone mixture to lighten. Fold in remaining whipped cream.
Hull and slice half of strawberries. Spread 1/2 cup of the jam mixture over the bottom of a 33x22x5 cm glass baking dish. Arrange enough ladyfingers over strawberry mixture to cover the bottom of dish.
Spoon 3/4 cup preserve mixture over ladyfingers, then spread 2 1/2 cups mascarpone mixture over. Arrange 2 cups sliced strawberries over mascarpone mixture. Repeat layering with remaining lady fingers, jam mixture, and mascarpone mixture. Cover with plastic membrane and chill at least 8 hours or overnight.
Slice remaining strawberries. Arrange over tiramisu and serve.