Preheat oven to 150 degrees C. Grease an 20cm springform pan with 1 tablespoon melted butter.
In a medium bowl mix together scone crumbs and 4 tablespoons melted butter. Press into the bottom of springform pan and smooth with the back of a spoon; set aside in the refrigerator to firm up.
Place the chocolate in a heatproof bowl. Heat cream to a simmer in a small saucepan; pour over white chocolate. Set aside for 1 minute then stir until smooth; set aside.
In a large bowl beat cream cheese until smooth. Mix in mascarpone cheese, sugar and egg yolks. Stir in white chocolate mixture and 1/2 cup passionfruit pulp. In a large glass or metal mixing bowl whisk egg whites until soft peaks form. Fold 1/3 of the whites into the batter very thoroughly then quickly fold in remaining whites until no streaks remain. Pour batter into prepared pan. Place the springform pan on a baking tray.
Bake for 1 1/4 hours in the preheated oven or until just set in the centre when shaken lightly. Turn off the oven and leave the cheesecake in the oven with the door ajar for 2 to 3 hours or until cool. Refrigerate for at least 2 hours.
Before serving, remove from pan and let stand at room temperature for 30 minutes. Dust with icing sugar and serve with pulp from 6 passionfruit.