Select equal sized potatoes. Peel them and carve out the insides to get boat-like shapes. Prepare a stuffing of the sautéed in oil finely chopped onions and some tomato pieces. When you remove them from the heat, add the crumbled feta cheese, eggs and parsley.
Fill the potatoes with the resulting stuffing, cover with the remaining tomatoes and oil and bake. After they soften, pour on béchamel sauce, made from the butter, flour, milk and egg yolks. Sprinkle with grated cheese and bake once again.
Serve with a green salad.