Mix the boiled and pierced potatoes in their skins with oil, flour, semolina, salt and knead with an egg. Roll it out on a floured board and cut it into approximately 4*4 cubes. Quarter the plums, roll them in cinnamon sugar and wrap them in the small dough squares. Add a little salt to the cooking water, boil it on a low heat, then the dumpling is good if it comes to the top of the water, this takes 2-3 minutes in hot water.