Cut mushrooms and onion finely, sautee in vegetable oil, stirring, for 10-15 minutes, season with salt and pepper.

Peel potato, rinse and slice.

Beat eggs up together with milk and cream, add grated cheese, salt, pepper and stir up.

Butter a baking tray and put in layers a half of potato slices and mushroom stuffing. Space potato slices over like tiles, cover with egg and milk mixture and bake about an hour at 430F (220C).

Garnish with finely chopped greens.