In a large pot or dutch oven, heat oil and butter on medium heat. Stir in chopped onion, carrot, and celery and cook for 6-8 minutes, or until the onion turns translucent.
Break beef into chunks and stir into the onion mixture. Add salt, pepper, and nutmeg. Once the meat begins to brown, stir in the milk and cook until it is absorbed in the meat.
Add wine and simmer until evaporated.
Add tomatoes to the pot and stir the mixture until the ingredients are covered in tomato juice. Once the sauce starts to boil, lower the heat so the sauce reaches a very low simmer and occasionally bubbles.
Allow sauce to simmer uncovered on low heat for 3 hours and stir occasionally. If the sauce dries out and is too thick, you may add a little water and stir, then simmer some more. Add more salt and pepper to taste.
In a separate pot, boil salted water. Once the water reaches a rolling boil, add the pasta and cook until al dente. For fresh pasta, cook for 2-3 minutes; for dry pasta, cook as instructed (typically around 8 minutes). Reserve 1 cup of pasta water and drain the pasta.
Add the pasta water to the sauce and stir. Cook on medium heat for 2-3 minutes. Remove the sauce from the heat and use tongs or a pasta fork to transfer the pasta to the sauce. Toss the pasta until evenly coated.
Serve in bowls and top with fresh Parmigiano-Reggiano.