Quickly knead together all dough ingredients on a cutting board until smooth, form a ball, and refrigerate wrapped in cling film for 60 minutes.
FOR THE FILLING, remove pits from the apricots and plums and replace them with one rum-soaked sugar cube each. Dip the strawberries in the rum and then roll them in granulated sugar.
On a floured board, shape the dough into a roll 5 cm thick and slice it into pieces weighing 30–40 g (depending on the fruit’s size). Flatten the pieces of dough somewhat, place fruit on top, and wrap the dough around them. Firmly press together the dough’s seams with your fingers and improve the dumplings’ shapes a bit with your hands. Place the dumplings in around 2 litres of lightly salted boiling water. After 1–2 minutes, carefully separate the dumplings from the bottom of the pot with a wooden spoon. As soon as the water begins boiling again, reduce heat and continue to cook the dumplings slowly until they rise and float on the surface. After another 2 minutes, lift them out of the cooking water with a perforated ladle. Refresh them in a pot filled with cold water and immediately roll them in a pan with butter-fried breadcrumbs. Place on a plate and sprinkle with icing sugar.