The potatoes are cleaned, washed, cut into cubes and boiled in salted water. The plums are washed, cut in half, the seeds are removed, cinnamon and sugar are added and the flavors are left aside to blend. Crush the potatoes as for puree, add 1 pinch of salt, the 2 yolks and mix. Add a little flour and mix again.
Well, here comes the hard part I say. To make good dumplings, you don't have to put too much flour, you don't have to make a hard dough that you knead on the work table. It is a deceptive dough that keeps asking for flour. When you have put enough flour to work with the dough, turn it over on the very well floured work table and take a spoonful of the dough. Roll it in flour, flatten it, put a piece of plum in the middle, gather the edges, glue and rotate and add a little more flour. They must be tightly closed otherwise they risk falling apart while boiling.
Put a pan of water to boil, and when it boils put the dumplings in water. Leave them for 3-4 minutes, they rise to the surface, take them with a foamer and put them on a plate.
Put the breadcrumbs in a pan with the caster sugar. Always stir in the breadcrumbs until it browns nicely. Finally add the raw sugar, the vanilla sugar, fry a little more and mix. Roll the dumplings through the breadcrumbs fried with sugar, and sprinkle the remaining one over the dumplings.