Peel and grate the raw potatoes, then squeeze out the excess liquid from them through a cheesecloth. Let the starch settle to the bottom of the liquid, then pour the liquid off and add the starch back to the potatoes. Peel and mash the boiled potatoes, then add them to the grated ones. Add a dash of salt and knead the mass well. Then take approximately egg-sized pieces of this mixture and form into patties. Place spoonfuls of the previously prepared filling into the center of the patties. Most often such a filling is made from ground beef, milk curd or mushrooms with salt and spices. Close the patties aroubd the filling and form them into ovoid shapes. Then place the cepelinai in salted boiling water and cook for approximately 30 minutes. Cepelinai are eaten with bacon or melted sour cream and butter sauce. This dish is very filling, and was traditionally only served for guests or during heavy labor seasons.