Hungarian Plum Knoedel

Boil several potatoes, mash, mix with one egg yolk, a little salt and enough flour to make a dough soft enough to hold the impress of the finger. Roll out and cut into four-cornered pieces; in each square place a German plum which has had the pits removed and a mixture of sugar and cinnamon; put in place of the pit. Roll each square into a round dumpling; put these into a pan with boiling; salted water and let them cook covered for six or eight minutes. When done, serve with some bread crumbs browned in butter or schmalz and spread over the knoedel.