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.