Boil the potatoes in cold water with a little salt. Let them cool a little, so that we can clean them, but not to cool them completely, and crush them until we get a kind of mashed potatoes. Melted the butter in a pan and over which fried the breadcrumbs. Fry for about 10-15 minutes, stirring constantly until it turns a golden colour.
Over the mashed and still hot potatoes, put flour and a teaspoon of salt, and break the two eggs over them. Knead the ingredients by hand until we obtain a homogeneous dough, which peels off the walls of the bowl but which will still be sticky. Put the dough on a work table well sprinkled with flour, so that the dough does not stick. Spread the dough with a paddle, up to 0.5-1 cm thick. Using a pizza cutter or knife, cut the dough into squares measuring approximately 10×10 cm.
Take one piece of dough in turn and put two prunes in the middle (or one plum). Pour a teaspoonful of sugar and cinnamon mix over the prunes. Join the four corners and roll in the hand until we get a ball. continue with the other squares, until we fill them all and get balls. From the edges of the remaining dough, we rolled some finger-sized shapes, which we do not fill.
Until we work with the dough, boil the water in a pot, together with a spoonful of salt, in which we will boil the dumplings. If the water has started to boil, put the dumplings in the water, 5-6 at a time, not more. After two minutes, if it has not risen to the surface, shake the pot a little because the dumplings tend to stick to the bottom of the pot. Boil the dumplings for about five minutes. Take them out with a spoon and roll them in the fried and sweet breadcrumbs, until they are completely covered.
Serve them warm with a little powdered sugar on top.