In a large heavy bottomed pot, heat the olive oil, add the beef, pork, veal and sausage (without casing) and cook until browned.
Add garlic and oregano and cook until fragrant.
Stir in the tomato paste and cook until the meat is coated.
Add tomatoes with their juices and the tomato puree, season with salt and pepper and bring to a boil.
Simmer over moderate heat, stirring occasionally, until thickened about 1 1/2 hours.
In large bowl, combine the ricotta with the parsley, basil, 1 cup of the Parmesan, 1 pound of the shredded mozzarella and beaten eggs. Season with salt and pepper.
The instructions suggested cooking the dry, curly-ridged lasagna noodles 3 minutes in abundant salted water, drained, rinsed -- I say use fresh, no-cook or even the curly edged pasta, and forget about the pre-cooking. I guarantee the sauce will cook the noodles after 45 minutes of cooking time. This also makes life much easier.
Preheat the oven to 375°F Spread 1.5 cup of the sauce in the bottom of a baking dish. Line the dish with overlapping noodles.
Spread 1/3 of the ricotta mixture over the noodles, sprinkle with a little Parmesan and shredded mozzarella then top with 1 1/2 cups of the sauce and another layer of noodles.
Repeat the layering 2 more times. Top with noodles and cover with 1 1/2 cups of sauce (may want to use extra if using uncooked noodles to ensure the noodles are covered and cook evenly. Sprinkle remaining mozzarella and Parmesan over the lasagna.
Cover Lasagna with foil and bake for about 20 minutes.
Uncover then cook for 30-45 minutes more or until the top is golden and crisp around the edges and the filling is bubbling.
Let the lasagna rest for 20 minutes before serving.