Preheat the oven to 350 degrees. Have ready a baking dish. Various sizes of baking dishes may be used to make lasagne, but one that measures 8 by 12inches is a good size.
Heat 2tablespoons of the oil in a skillet and add the onion and garlic. Cook until the onion is wilted and add the meat. Cook, breaking up the lumps in the meat with the side of a metal kitchen spoon. Cook and stir until the meat loses its red color. Add salt and pepper and tomato sauce. Bring to a boil and simmer for 20 minutes.
Meanwhile, pour the 6quarts of water into a large kettle and add 3tablespoons of salt, and the remaining tablespoon of oil. When it is boiling rapidly, add the lasagne noodles and cook until softened. Stir it around continuously with a wooden spoon so that it does not stick to itself or the bottom of the kettle. When the water starts to boil violently again, let the lasagne cook for from 12 to 15 minutes, or until it is done. Do not overcook it. Remember that the lasagne will cook further when it is baked in the oven.
Spoon a thin layer of the meat sauce over the bottom of the baking dish and arrange a flat layer of the lasagne noodles over it. Spoon a layer of meat sauce over the lasagne. Cut the mozzarella cheese into thin slices and arrange one layer of mozzarella over the meat sauce. Spoon some ricotta cheese over this and a little Parmesan cheese. Add another layer of noodles, more meat sauce, mozzarella, ricotta, and Parmesan. Continue making layers, ending with meat sauce and Parmesan. Up to this point the lasagne may be made in advance and refrigerated.
When ready to cook, place the lasagne in the oven and bake20 minutes or longer, or until it is piping hot throughout and bubbling. Serve, if desired, with additional grated Parmesan cheese.