Drain the curd well. Remove the crusts from the bread and dice finely. Cream 60 g butter, 4 tablespoons sugar and vanilla sugar. Stir in egg yolks, eggs, quark, lemon peel and lemon juice, then bread. Chill for 3 hours.
Meanwhile wash, halve and stone the plums. Boil 1/8 l water, 75 g sugar and cinnamon stick. Cover the plums and stew them for 5-8 minutes.
Remove the cinnamon stick. Stir 1 tablespoon starch and 3 tablespoons water until smooth. Bring the plums to the boil, stir in the starch and simmer for 2-3 minutes while stirring. Let the compote cool down.
Cut off the curd mixture in portions with a tablespoon and carefully form into dumplings with floured hands (the mixture is very tender!). Place on a lightly floured plate.
Bring 2-3 l water and 1-2 teaspoons of salt to the boil in a wide saucepan. Add the dumplings and cook at low heat for 12-15 minutes. Remove with a skimmer and drain on kitchen paper.
Finely grate the toast between your hands. Melt 2-3 tablespoons of butter in a large pan. Roast the toast crumbs in it until golden brown. Sprinkle in 1 tbsp. sugar. Swivel dumplings in it. Serve with plum roaster.