Brown meat with onion, salt and pepper. Drain any extra fat. Add tomatoes and tomato sauce to browned meat. Add garlic, oregano and parsley, to taste. Stir and simmer until thickened.
Melt butter in skillet. Mix in flour and salt, stirring until smooth. Add milk and cheese. Cook over low heat till sauce is like heavy cream. Do not boil.
Put it all together: Spread a thin layer of sauce over bottom of a large, deep lasagna pan. Cover with single layer of oven-ready lasagna noodles (you’ll need two standard boxes of noodles for this dish). Top with a layer of grated mozzarella cheese. Continue layering sauce, noodles and grated cheese until there’s three inches of room left to the top of the pan. Add a layer of sauce and then pour the cheese sauce over the top. Bake at 350°F for 1 1⁄2 to 2 hrs. Noodles are cooked when a sharp knife inserted through the middle comes out smoothly. Turn oven on broil for 2 or 3 min. to brown the top. Remove from oven and let sit at least 15 min. before cutting.