Peel the potatoes, boil them for 20 minutes until soft and put through a potato press.
Mix them with a pinch of salt, 50 g of sugar, grated lemon zest, 50 g softened butter and 2 eggs.
Add in the flour, mix together and knead well, adding a bit of water if necessary.
Roll out the dough into floury cutting board surface and cut into square pieces.
Add one plum and 1 tsp of sugar on top per piece, then roll each dumpling, flatten it and wrap it around a pitted plum.
Pour water to a big pot and bring it boiling, add a bit of salt. Put in the dumplings when the water is boiling, and cook until they float to the surface. Once they do, cook for another 5 minutes and remove from water.
Serve with melted butter, sweetened cream and sprinkle with cinnamon.