Cut out one Viennese cake base to a circle of 19 cm Ø, a second one to 14 cm Ø. Peel, halve and core one papaya. Puree the flesh. Whip the cream with cream firmer until stiff. Mix mascarpone, quark and papaya puree.
Add lime juice, vanilla sugar and sugar. Fold in cream. Peel, halve and core the remaining papaya. Cut one fruit into columns, the other into cubes. Wash the carambola thoroughly, dab dry and cut into slices. Remove the seeds from the melon and use a ball cutter to twist balls out of the flesh. Cover the largest base in the middle with a few slices of papaya. Spread some cream on it and place the middle cake base on top. Cover the middle cake base with the remaining papaya slices. Spread some cream on it and place the smallest cake base on top.
Cover the largest base in the middle with a few slices of papaya. Spread some cream on it and place the middle cake base on top. Cover the middle cake base with the remaining papaya slices. Spread some cream on it and place the smallest cake base on top. Spread the remaining cream all around the cake. Decorate with the fruit and lemon balm leaves. Makes about 16 pieces