Boil unpeeled potatoes in salted water for 30 minutes, drain them and let them cool. Peel the potatoes and cut them in 1/5-1/4 inch (5-6 mm) slices.
Boil eggs for 8 minutes, let them cool with cold water. Peel them then shred them.
Preheat oven to 395 F (200 C).
Peel and cut sausage in medium-thick slices. Fry sausage slices in a frying pan for about 5 minutes over medium heat.
Prepare the béchamel sauce. Melt butter in a saucepan over medium heat, add flour and let it cook for 2-3 minutes. Pour in hot milk while whisking constantly and vigorously. Lower the heat and let the flour cook for 2-3 minutes while constantly stirring. Season with salt, ground nutmeg and black pepper. Let it cool a couple of minutes then mix in 1 ½ cups sour cream.
Place down 1/3 of the potatoes as the first layer in a lightly greased, 9 by 13 inch (approx. 25x35 cm) baking dish. Salt potatoes according to taste.
Follow with 1/2 of the eggs, spread evenly and salt according to taste.
Sprinkle with 3 tbsp sausage fat, spread 1/2 of the sausage evenly then cover with 1/2 of the bechamel sauce.
Make a second layer just like the first one. 1/3 potatoes, salt, 1/2 (remaining) eggs, salt, 3 tbsp. sausage fat, 1/2 (remaining) sausages and finally 1/2 (all remaining) bechamel sauce.
Finish with a layer of the remaining potatoes, then spread the remaining sour cream and finally sprinkle with breadcrumbs.
Bake for 40 minutes uncovered.