01 -
Bring salted water to a boil. Add potatoes and cook until tender, about 15 minutes. Drain thoroughly and let cool completely.
02 -
Mash cooled potatoes until smooth. On a floured surface, combine potatoes with flour, egg, sour cream, and salt. Knead gently until dough forms; add more flour if needed for non-stick consistency.
03 -
Flatten portions of dough into small discs. Place one plum half in the center of each disc, sprinkle lightly with cinnamon and powdered sugar, then encase the plum with dough, forming sealed balls.
04 -
Bring a large pot of salted water to a gentle boil. Slide dumplings into water in batches; simmer until they rise to the surface, then cook for 5 minutes more.
05 -
Remove dumplings using a slotted spoon and drain well. Arrange on plates.
06 -
In a skillet over medium heat, toast breadcrumbs until golden. Add melted butter and mix to coat evenly.
07 -
Spoon buttery breadcrumbs over the dumplings. Accompany with sweetened sour cream and serve immediately.