Similar dish exists in Lithuanian cuisine which Lithuanians named Cepelinai. If I am not mistaken Polish cuisine has a similar dish. I can’t remember the name. Cepelinai are so popular in Lithuania that Lithuanians establish competions on who can eat more and quicker cepelinai. Crazy!
I will post video of Belarusian kliocski, which is a simple dish of common folks. I would have cooked it differently. I would remove brown matter from mushrooms. I would use different types of mushrooms grown in forests. I will also soak onion in cold water and wash it to remove bitter smell and taste. Then white pepper, coriander and nutmeg will be added. Mince has to be made at home.
Of course, sauce is based on sour-cream. I would use mustard, white pepper and mustard seeds in making sauce.