Make the Bolognese. Put onion, carrot, celery, garlic, and sage in a food processor and process until you have a smooth vegetable pulp. Coat a large, heavy pot with oil and set over medium heat. Add vegetable pulp and saute until fragrant and some of the moisture has evaporated, about 5 minutes. Push the vegetable mixture to one side of the pan. Season ground beef and pork with salt and pepper and add to pan. Stir and break up meat until it is brown, then dust with the flour before adding wine, tomatoes, milk, and cinnamon. Bring to a boil, then reduce heat and simmer about 1 1/2 hours, uincovered, until sauce is thick. Add parmesan and parsley and season with salt and pepper if needed. Set aside while you make the bechamel.
To make the bechamel, set a large saucepan over medium heat. Add milk, garlic, and bay leaf and bring to a simmer to infuse milk with herbs. set a large saucepan over medium low heat. Add butter and melt, then sprinkle with flourwhile stirring with a wooden spoon. Once flourhas been combined with butter, grab a whisk and gradually pour in the herb infused milk, passing it through a sieve to strain out the aromatics. As the sauce thickens, continue to whisk over low heat, then add nutmeg. Season with salt and pepper and set aside to cool slightly.
Preheat oven to 350°F To assemble the lasagna, cut fresh pasta to fit pan if needed. Coat the bottom of a 13x9 pan with a thin layer of bechamel. Top with a layer of lasagna noodles. Top noodles with a layer each of bechamel, bolognese, and mozzarella pieces. Continue with layers until you have three complete layers, finishing with mozzarella.Sshower the top of the lasagna with parmesan and parsley. Bake, uncovered, on a tray ( to catch drippings) in the center of the over for 1 hour. If the top starts to brown tent with foil. Let the lasagna stand for 30 minutes before cutting.