Let the potatoes cool to the touch, then mash them.
Add the flour, semolina flour, egg yolks, and butter, and then first with a spoon and later with your hands, mix it into a smooth dough. Don't overwork the dough to prevent it becoming gooey.
Shape the dough into a log and divide into eight portions (maybe less if your fruits are large).
Take one of the plums or apricots, remove the stone and replace it with a sugar cube.
Wrap one dough portion around the fruit, close the seam well and repeat with the remaining fruits and dough.
Fill a large pot with water and add a bit of salt, bring to a simmer and add the dumplings.
Let the dumplings simmer for about 13 to 15 minutes.
In the meantime, melt the butter in a pan.
Add the bread crumbs and stir. Fry until golden.
Serve the dumplings on a bowl or on a plate with the bread crumbs on the bottom. You can put some bread crumbs on top of the dumpling or roll it in them entirely to cover it.
Sprinkle some confectioners sugar on top.
Tip: If you want things a bit more sweet, mix some confectioners sugar in the golden bread crumbs.