Slice the Jerusalem artichokes very thinly, put them in a baking dish with butter, olive oil, salt and pepper. Cook them slowly until done, about 30 minutes. Mix them with a mixer, prepare a rather thick béchamel and add it to the Jerusalem artichokes.
Add the grated cheese and eggs and pour into a buttered and floured mold.
Bake at 180°C(355°F) for about 1 hour. It is served as a side dish with scallops, mushrooms or cotechino.