Dissolve the yeast in some lukewarm milk. Put flour, sugar and salt in a bowl and make a depression in the middle. Add the yeast-milk mixture and sprinkle with some flour. Cover and leave to rise in a warm place for about 30 minutes.
Add the remaining milk, lemon peel, egg, fat and hazelnuts and knead to a smooth dough. Leave to rise for another 30 minutes. Form dough into a roll and divide into 15 pieces. Form into balls and place them side by side in a greased casserole dish.
Pour on milk and bake in the oven (electric: 200 °C/ gas: level 3) for 35-45 minutes. In the meantime, pour plums onto a sieve, collecting the juice. Mix 4 tablespoons of juice with starch.
Boil up the rest of the juice with plum brandy, sugar, cinnamon and lemon peel, stir in the starch and bring to the boil again. Fold in plums. Remove cinnamon stick and lemon peel. Sprinkle with chopped hazelnuts and serve hot or cold with the steamed pasta.
Decorate with lemon balm.