Put flour, crumbled yeast, sugar, salt, egg and sour cream in a bowl. Warm the whipped cream slightly and melt the fat in it. Pour in and knead everything into a smooth dough.
Cover and leave to rise for about 30 minutes. In the meantime, boil down the sugar and 4 tablespoons of water until syrupy. Wash and quarter the apple and remove the core. Grate apple roughly.
Finely dice the quince. Mix apple, quince, hazelnuts, almonds, jam, raisins and vanilla pulp with the sugar syrup. Knead the yeast dough again and roll out to a rectangle of 50 x 40 cm on a floured work surface.
Spread the filling over it, leaving a rim of about 2 cm free. Roll everything up and place on a baking tray lined with baking paper. Leave to rise for another 15 minutes. Brush with egg yolk and bake in a preheated oven (electric: 175 °C/ gas: level 2) for about 60 minutes.
Results in about 40 pieces.