Potatoes wash, peel and boil in salted water. Eggs boil, clean.

Allow to cool our products. Eggs cut into round slices.

Potatoes - as well.

Sauce: In a saucepan heat the butter, add the flour and sauté until Golden brown. After that pour the hot milk and cook until thick (continuously interfere, to avoid lumps). When the sauce starts to let the "bubbles", so it is possible to turn off - he's ready. Add lemon juice, salt (to taste). Allow to cool for about 15 minutes, introduce the egg yolk and mix thoroughly.

Cheese to grate on a coarse grater.

Potatoes and eggs are laid in layers in a fireproof dish, pour the sauce, cover with grated cheese on top put a few slices of butter. To put bake in the preheated oven until Golden brown cheese.