In a large dutch oven or soup pot, add the olive oil, 6 Tablespoons of butter and the onions.
Heat over medium heat and cook the onions until they are translucent. Do not brown the onions. If the onions start to brown a bit around the edges, reduce the heat.
Add the carrots and celery and cook for a couple of minutes.
Add the beef and pork. Season with salt and pepper.
Cook until the beef and pork are no longer pink, crumbling the meat with a wooden spoon or spatula.
Add the milk and let simmer until the milk has evaporated, stirring frequently for about 30 minutes.
Add the nutmeg and stir.
Add the wine, stir and simmer until the wine evaporates, about 30 minutes.
Add the tomatoes and their juices and stir to combine., Increase the heat until the mixture begins to bubble. Turn the heat to low, simmer (i.e. a bubble only breaks the surface every so often).
Cook, uncovered for approximately 3 hours, stirring occasionally.
If the sauce begins to dry out, add about ½ cup of water and stir, making sure to scrape the bottom of the pan.
Cook and drain the pasta and toss with the sauce and the remaining butter.
Divide between low bowls and top with grated parmesan if desired.