Roll out quite thin and cut into rounds the diameter of a teacup.
Remove pits from the plums and fill each cavity with a sugar cube. Place 1 filled plum in each round of dough and pinch edges together.
Cook in lightly salted boiling water about 10 minutes. While the dumplings are cooking, mix the bread crumbs with the melted butter. When dumplings are cooked, drain and roll in bread-crumb mixture and then in sugar and cinnamon.
These are a delicious accompaniment to either roast beef or roast pork.