In a large, heavy-bottomed Dutch oven over medium heat melt butter; add onion, carrot, celery, garlic, and pancetta and sautè until softened but not browned, about 6 minutes. Add ground meat and 1/2 teaspoon salt;
Crumble the meat with the edge of a wooden spoon to break apart into tiny pieces so no clumps remain. Cook, continuing to crumble meat, just until it loses its raw color but has not yet browned, about 3 minutes.
Add milk and bring to simmer; continue to simmer until milk evaporates and only clear fat remains, 10 to 15 minutes.
Add wine and bring to simmer; continue to simmer until wine evaporates, 10 to 15 minutes longer.
Add tomatoes and their juice and bring to simmer; reduce heat to low so that sauce continues to simmer just barely, with an occasional bubble or two at the surface, until liquid has evaporated (wooden spoon should leave trail when dragged through sauce), about 3 hours. Adjust seasonings with extra salt to taste. Keep sauce warm.
Bring 4 quarts water to boil in large pot. Add pasta and 1 tablespoon salt and cook, stirring occasionally, until al dente. Drain pasta, leaving some water dripping from noodles. Toss with sauce and remaining 2 tablespoons butter. Distribute among individual bowls and serve immediately, passing Parmesan cheese separately.