Peel the potatoes and cube. Cook them in salted water for 20 to 25 minutes. Remove from heat as soon as the tip of a knife can pierce one easily. Drain the potatoes perfectly and mash with potato masher. Let the mashed potatoes cool completely. (Generally we cook and mash the potatoes the night before.)
In large bowl mix the potato and eggs with a fork.
Add flour and pinch of salt. Mix until a soft dough forms. Cover the dough with plastic wrap and let it rest for 30 minutes.
Brown the breadcrumbs in the oil.
Place a large pot of salted water on to boil.
In small bowl mix 2 tablespoon sugar with 1 teaspoon cinnamon powder.
On a lightly floured surface, roll the dough to 1 cm (1/3 inch). Cut into 5-cm (2-inch) squares.
Cut in half each plum and roll them in the sugar-cinnamon mix.
Put a plum in the middle of square dought. Flour your hands. Pinch the edges of the dough together and rolling it to form a ball.
Drop the dumplings into the salted boiling water one by one. Cook 5-6 duplings at time. Boil gently uncovered for 6 to 8 minutes after they rise to the surface.
When the dumplings are done, remove them carefully, roll them in the breadcrumbs.
Serve warm with cinnemon sugar mix.
Notes
The dough of plum dumplings is resembles Italian gnocchi.