Peel, boil, drain and mash potatoes. Let cool to room temperature.
Add in eggs, salt and flour. Knead well. (You don't really need to add the whole flour. When you feel that it is enough while kneading, stop adding. Dough should be soft to the touch, not crumbly, but also not too doughy).
Divide dough into 3 portions, and roll flat each one. (You can do this right away, or let dough rest for half hour, covered. Some people like to store it in the fridge before rolling, that is okay as well).
Slice into squares, as shown on picture.
Place 1 slice of filling, roll round.