Saute while stirring nonstop until they're left in just oil. Peel and chop the potatoes into thin slices, chop the tomatoes into thin slices as well.
In a rectangular tray, smeared with the remaining oil, arrange a layer of tomatoes, then layer of potatoes and salt to taste. Distribute the sauteed mince evenly on top, then another layer of potatoes and tomatoes.
Pour in water up to the level of the potatoes and bake in a preheated 428°F (220 °C) oven until the potatoes are ready.
Beat the egg, add the flour and milk, stir to a smooth mixture and salt to taste.
Pour this mixture over the moussaka, sprinkle with the grated cheese and bake again until the cheese gains a golden-brown crust.
A juicy and very tasty layered moussaka - brought to you by Bai Dancho.