Butter 4 square small tart pans about 12 cm in diameter (approximately 5 inches).
Thaw filo dough and cut into squares. Layer dough in tart pans (2-3 layers), overlapping.
Rinse and pit plums, pat dry.
Separate eggs. Whisk egg yolks with quark, cream, sugar and creme fraiche until smooth. Beat egg whites until stiff and fold into cream. Spread on dough and top with plums. Bake in preheated oven at 180°C (approximately 350°F) for about 40-45 minutes or until golden brown.
Cool and sprinkle with cinnamon sugar. Serve.