Use a baking tray. Combine the flour (reserving 1 tbsp) and the sugar in a large mixing bowl. Cut in the chopped butter and the cream cheese with 2 knives until mixture resembles coarse crumbs. Combine sour cream and 1 tbsp iced water in a small bowl; stir into flour mixture just until combined. Flatten dough into a round, wrap in cling wrap and refrigerate for at least 1 hour.
Preheat oven to 190 degrees C. Roll out dough on a floured surface to a 33cm round. Place on a baking tray and roll the edges over once to form a neat edge.
Brush dough with the beaten egg white. Arrange the plums on top in overlapping concentric circles. Combine the sugar, ginger, pepper and the remaining flour in a small bowl. Sprinkle evenly over the plums. Bake for 40 minutes or until the plums are tender and the crust is golden.