Peel the eggplants and cut them into slices about 1 cm thick. Brown the slices quickly in quarter cup of the oil. Set aside. Heat the remaining oil in the same skillet and cook the onions until they are brown. Add the ground meat and cook 10 minutes. Pour off excess fat. Combine the tomato paste with the wine, parsley, cinnamon, salt and peper. Stir this mixture into the meat and simmer over low heat, stirring frequently, until all the liquid has been absorbed. Remove the mixture from the fire. Preheat the oven to 190ºC . Make a white sauce by melting the butter and blending in the flour, stirring with a wire whisk. Meanwhile, bring the milk to a boil and add it gradually to the butter-flour mixture, stirring constantly. When the mixture is thickened and smooth, remove it from the heat. Cook slightly and stir in the beaten eggs, nutmeg and ricotta. Grease an 11x16-inch pan and sprinkle the bottom lightly with crumbs. Arrange alternate layers of the eggplant and the meat sauce in the pan, sprinkling each layer with Parmesan and crumbs. Pour the ricotta sauce over the top and bake 1 hour, or until top is golden. Remove from the oven and cool 20 to 30 minutes before serving. Cut into squares and serve. The flavors in this dish really improve if you make it a day ahead.